Here’s a confession: the first time I heard the phrase 'substitute decision-maker,' I pictured someone picking between tea or coffee for an indecisive friend. But in Australia’s Advance Care Planning landscape, this role can carry the weight of life-altering medical, financial, and lifestyle decisions. Sometimes, it’s straightforward—the granny who’d rather watch footy than go to the doctor gets her way, thanks to her daughter’s calm advocacy. Other times, it’s messy: siblings squabbling at a hospital bedside, or a court grappling with what ‘Mum really wanted’. If you’re trusting someone with your future choices, you need more than a quick signature on a form. Dive in for the (occasionally bumpy) insider’s tour of what substitute decision-makers can and can’t do, and how digital tools like Evaheld might just save the day.
The Many Faces of Substitute Decision-Makers: Who Holds the Keys?
When it comes to Advance Care Planning (ACP) in Australia, the term substitute decision-maker covers a wide range of roles and responsibilities. These are the people who may be called upon to make crucial decisions—medical, personal, or financial—if someone loses capacity. Understanding who can act as an ACP substitute decision maker in Australia, how they are appointed, and what happens if you do not appoint one is essential for ensuring your wishes are respected.
Variety of Substitute Roles: More Than Just a Guardian
Substitute decision-makers come in several forms, each with specific powers and limits. The most common roles include:
- Enduring Guardian: Appointed to make lifestyle and health decisions, such as medical treatment or accommodation choices (Lamrocks Solicitors).
- Enduring Power of Attorney: Handles financial and property matters (EPG Wealth).
- Medical Decision-Maker: Specifically appointed for health care decisions, sometimes under different titles depending on the state.
- Default Decision-Maker Substitute: If no one is appointed, state laws set out a hierarchy of who steps in by default (e.g., spouse, adult child, parent).
Each state and territory in Australia has its own rules, forms, and terminology for these roles (Lawpath). For example, in New South Wales, the Ageing & Disability Commission outlines the duties, limits, and appointment process for substitute decision-makers.
Appointment: State-by-State Differences
There is no one-size-fits-all system for decision maker appointment state-by-state in Australia. The minimum age to appoint a substitute is generally 18, but some jurisdictions, such as South Australia, allow appointments from 16. The forms and witnessing requirements also differ. For example:
- NSW: Enduring Guardianship and Enduring Power of Attorney are separate appointments, each with their own forms and witnessing rules.
- Victoria: Medical Treatment Decision Maker and Enduring Power of Attorney are distinct roles.
- Queensland: Advance Health Directive, Enduring Power of Attorney, and default statutory health attorney are options (Queensland Estate Lawyers).
Default vs. Personally Appointed: What If You Don’t Decide?
If you do not appoint an advance care planning substitute in Australia, the law steps in. Each state has a default decision-maker substitute hierarchy. This can mean a spouse, adult child, parent, or close friend may be called upon—sometimes leading to confusion or disputes if your wishes are unclear or family relationships are complex.
Court and Tribunal Involvement: When Things Get Complicated
Disputes, incapacity, or unclear appointments may require intervention by courts or tribunals such as NCAT (NSW Civil and Administrative Tribunal), the Supreme Court, or the Mental Health Review Tribunal. These bodies can appoint a Public Guardian or Trustee, or resolve conflicts between multiple potential decision-makers.
“A substitute decision-maker can only make a decision on your behalf if you lack capacity for that matter.” – Lamrocks Solicitors
Supported decision making is always preferred, but when capacity is lost, the legal authority of a properly appointed or default substitute decision-maker is binding. Verifying decision maker Australia processes, and keeping your ACP up to date—digitally via platforms like Evaheld—ensures your chosen substitute holds the keys when it matters most.
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What They Can and Can’t Decide: Legal Limits and Lodged Values
In Australia, the authority of a substitute decision-maker (SDM) is carefully defined by law and guided by the person’s own values and wishes. Understanding substitute decision maker limits in Australia is crucial for anyone involved in Advance Care Planning (ACP), whether appointing, acting as, or supporting an SDM. Their powers are not unlimited, and their core duty is to act as the individual would want, not simply in what they believe is the person’s best interests.
Boundaries: What Substitute Decision-Makers Cannot Do
- Cannot make illegal decisions: SDMs must always comply with Australian law. They cannot authorise actions that are unlawful, such as euthanasia or assisted dying (unless expressly permitted under specific state legislation).
- Cannot refuse basic comfort care: No SDM can deny fundamental care such as food, water, pain relief, or hygiene. Statutory limits explicitly prevent refusal of these basic supports, even if other treatments are declined (NSW Ageing & Disability Commission).
- Cannot override clear, documented wishes: If an Advance Care Directive (ACD) or ACP record exists, the SDM must follow it. Their authority is subordinate to the person’s own stated preferences and values (EPG Wealth).
Types of Decisions: Medical, Lifestyle, and Financial
Substitute decision maker authority in Australia is divided into distinct categories, each with its own legal framework:
- Medical decisions: Includes consenting to or refusing treatments, surgeries, or interventions. However, statutory overrides apply—certain life-sustaining measures or end-of-life choices may require practitioner judgment or tribunal approval (Queensland Estate Lawyers).
- Lifestyle/personal decisions: Covers accommodation, daily living arrangements, and support services. SDMs may decide on moving to aged care, but cannot force illegal or unsafe living conditions (Lamrocks Solicitors).
- Financial decisions: Only an Enduring Power of Attorney (EPOA) can manage property, banking, and assets. Guardians or medical SDMs have no authority here (Lawpath).
Fiduciary Duty: Acting in Accordance with Values and Directives
SDMs have a fiduciary duty—a legal and ethical obligation to act in good faith, avoid conflicts of interest, and keep detailed records of decisions. Their paramount responsibility is to honour the person’s own wishes, values, and Advance Care Directives. As EPG Wealth notes:
“It’s not about what you think is best, but about honouring the choices the person would have made.”
Where wishes are unclear, SDMs must act in the person’s best interests, but always with reference to any available value statements or ACP documentation. Tools like Evaheld’s digital ACP help ensure these records are accessible, up-to-date, and guide SDMs to stay aligned with the individual’s preferences.
Statutory Overrides and Practitioner Judgment
Some decisions, especially regarding life-sustaining treatment, are subject to statutory limits and require medical or tribunal oversight. For example, withdrawing life support or making major accommodation changes may need additional legal or clinical review, depending on state law.
Ultimately, substitute decision-maker duties in Australia are about respecting autonomy within clear legal and ethical boundaries, ensuring that the person’s voice remains central even when they cannot speak for themselves.
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Family Feuds & Ethical Quandaries: When Substitute Decision-Making Gets Messy
Few things test family bonds like the appointment of a substitute decision-maker in an Advance Care Plan (ACP). While the intention is to ensure a person’s wishes are respected, the reality is often far more complicated. In Australia, decision maker family conflict is one of the leading causes of ACP breakdowns, with disputes frequently landing before tribunals or courts such as NCAT or the Supreme Court [NSW Ageing & Disability Commission].
Common Disputes: Siblings, Estranged Relatives, and Vague Directives
It’s not uncommon for siblings to disagree on what Mum or Dad would have wanted, especially if the ACP is unclear or contains conflicting instructions. Estranged relatives may challenge the validity of an appointment, claiming undue influence or lack of capacity. Sometimes, the directive itself is so vague that interpretation becomes a battleground. As one lawyer quips,
“Some families will fight about who chooses the colour for Mum’s curtains—now picture trying to agree on end-of-life wishes.”
These disputes can escalate quickly, especially when emotions run high and communication breaks down.
Legal and Ethical Duties: Avoiding Conflicts of Interest
Australian law sets clear fiduciary duties for substitute decision-makers. They must:
- Act in the person’s best interests, not their own [Lawpath]
- Avoid conflicts of interest and personal gain [Lamrocks Solicitors]
- Keep accurate records and document all decisions
- Report suspected abuse or irregularities
Failure to meet these standards can trigger intervention by a tribunal substitute decision maker or even the appointment of a professional such as the Public Guardian or Trustee [EPG Wealth].
Role of Tribunals and Courts in Disputes
When families cannot resolve their differences, or when there are allegations of misconduct, tribunals and courts step in. NCAT and the Supreme Court regularly mediate disputes decision maker Australia, including:
- Challenging the validity of an appointment
- Allegations of financial or medical abuse
- Concerns about capacity or undue influence
In some cases, the tribunal may revoke the appointment and install a neutral party, such as the Public Guardian [Queensland Estate Lawyers].
Managing Family Dynamics: Practical Tips
- Communicate early and often with all relevant family members
- Document wishes and decisions clearly—digital ACPs (like Evaheld) help maintain transparency
- Consider appointing joint or backup decision-makers to reduce the risk of deadlock
- Seek professional advice if family conflict seems likely
Ultimately, the ethical duty of a substitute decision-maker is to prioritise the person’s values and wishes—no matter how messy the family dynamics become.
Keeping It Above Board: Duty, Documentation, and Digital Innovation
In Australia, the responsibilities of a substitute decision-maker (SDM) within Advance Care Planning (ACP) extend far beyond simply “doing what’s best.” Legal compliance, robust documentation, and transparent decision-making are not just best practice—they are essential protections for all involved. As the NSW Ageing & Disability Commission highlights, the SDM’s role is defined by strict fiduciary duties, statutory limits, and a clear expectation of accountability (NSW Ageing & Disability Commission PDF).
Record-Keeping: The Backbone of Good Substitute Decision-Making
Every significant decision made by an SDM—whether about medical treatment, living arrangements, or financial matters—should be carefully documented. This record-keeping is not just about ticking boxes; it is a legal and ethical safeguard. As Lawpath and Lamrocks Solicitors explain, thorough documentation helps demonstrate that the SDM acted within their authority and in line with the person’s values and directives.
- Traditional methods: Handwritten diaries or logbooks remain valid, but are prone to loss or damage.
- Digital ACP solutions: Platforms like Evaheld allow SDMs to upload substitute decision-maker details, directives, and real-time records, ensuring secure and centralised access.
Audit Trails: Proving Accountability and Preventing Disputes
Audit trails are especially critical for financial and property decisions. A clear, chronological record of actions and decisions—who did what, when, and why—can be the difference between a smooth process and a contested one. As EPG Wealth and Queensland Estate Lawyers note, a digital ACP substitute in Australia can provide an audit trail that is tamper-resistant and easily accessible for review.
“You can’t ‘wing it’ as a substitute decision-maker—paper trails and digital logs are your best friends.”
Digital Innovation: Centralising and Securing ACP Documentation
There is a growing uptake of digital ACP platforms in Australia, driven by the need for clarity, accessibility, and protection of sensitive information. Services like Evaheld enable users to upload substitute decision-maker details, directives, and supporting documents, creating a single source of truth. This centralisation reduces the risk of lost paperwork, miscommunication, and family disputes, while also supporting legal compliance and privacy obligations.
Training and Support: The Missing Manual
Despite the complexity of their responsibilities, most SDMs receive little formal training. Real-world scenarios—such as balancing family conflict, interpreting ambiguous directives, or responding to urgent medical decisions—require more than a basic understanding of the law. Digital ACP platforms often provide guidance, checklists, and reminders, helping decision-makers navigate their duties with confidence and transparency.
Ultimately, good documentation is a key defence if an SDM’s actions are ever questioned by courts, health professionals, or family members. Embracing digital ACP solutions is not just about convenience—it’s about upholding the highest standards of ethical, legal, and practical accountability.
Choosing Wisely: Future-Proofing Your Advance Care Plan—And Your Peace of Mind
Appointing a substitute decision maker in Australia is one of the most important steps in advance care planning. Yet, too often, people default to convenience or tradition—choosing a close family member or friend without considering whether that person truly understands their values, or is prepared for the responsibilities involved. As the NSW Ageing & Disability Commission highlights, a substitute decision maker’s role is not merely administrative; it is a fiduciary duty, requiring careful judgement, respect for your wishes, and legal compliance (NSW Ageing & Disability Commission).
When considering a substitute decision maker appointment in Australia, it is crucial to select someone who is reliable, communicative, and aligned with your beliefs. As the saying goes,
“Your best mate at the pub might not be the best mate for making life-and-death calls—choose thoughtfully.”
The person you appoint should be comfortable making difficult decisions, able to advocate for you, and willing to engage with your advance care plan in detail. Involving them in the creation of your ACP ensures they understand your wishes and the reasoning behind them (Lawpath).
To future-proof your plan, always consider appointing a backup substitute decision maker. Life is unpredictable—your primary appointee may be unavailable, unwilling, or unable to act when needed. Including alternates, or even joint decision makers, adds resilience and helps prevent disputes or delays in urgent situations (Lamrocks Solicitors). In some states, you can formally appoint multiple or joint decision makers, which can be especially useful for complex family dynamics or when a broad range of decisions (medical, lifestyle, property, living arrangements) must be covered (EPG Wealth).
Most disputes in advance care planning arise from vague, outdated, or incomplete directives, or from the absence of alternate decision makers (Queensland Estate Lawyers). To avoid this, be specific and explicit in your Advance Care Directives. Detail your preferences for medical treatment, living arrangements, property management, and even smaller lifestyle choices. Regularly review and update your ACP, especially after major life events or changes in health status. State-by-state forms and witnessing requirements vary, so ensure your documentation is compliant and up to date.
Technology now offers creative solutions for clarity and peace of mind. Digital ACP platforms like Evaheld allow you to upload your directives, record video statements, and set reminders for periodic review. These tools help your substitute decision maker stay aligned with your evolving wishes and provide an accessible, auditable record for all involved.
Ultimately, a careful, values-driven approach to appointing and supporting your substitute decision maker—backed by clear, detailed directives and the right technology—can protect your autonomy and spare your loved ones unnecessary stress. Advance care planning is not just about forms; it’s about ensuring your voice is heard, now and into the future.
Future-Proof Your Voice, Care, and Legacy with the Evaheld Legacy Vault
Your life is a collection of stories, wishes, and connections that deserve to be protected and shared. The Evaheld Legacy Vault provides a secure, organised, and shareable digital home for everything that matters—giving you and your loved ones enduring peace of mind across generations.
Take control of your future care and legacy today. With Charli, your dedicated AI assistant, you can easily set up your free Evaheld Legacy Vault to keep your advance care plans, essential documents, and family stories instantly accessible to loved ones, carers, and healthcare professionals—ensuring your voice and wishes are always protected.
Take control of what matters most — set up your free Evaheld Legacy Vault to keep your stories, care wishes, and essential documents safe, organised, and instantly shareable with loved ones and advisers, for life.
TL;DR: Substitute decision-makers in Australia wield serious authority in advance care planning, yet face strict legal and ethical limits. They must put your wishes before their own, avoid conflicts, keep good records, and can get tangled in disputes—so pick and document wisely. Digital platforms like Evaheld offer checks and support so your values stay centre stage, no matter who’s at the wheel.
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