Substitute Decision Maker Northern Territory: How to Choose and Appoint One

What a Substitute Decision Maker Is in the NT

In most Australian states, you appoint an "attorney" under a power of attorney. In the Northern Territory, the term is "decision-maker" — appointed under an Advance Personal Plan. The role is functionally the same: a trusted person who can act on your behalf when you lose decision-making capacity.

The NT does not use the term "healthcare proxy" in its legislation, but the concept maps directly to a decision-maker appointed with healthcare authority under an APP.

Three Types of Authority

When you appoint a decision-maker in your APP, you specify which areas they can act in:

Financial — managing bank accounts, paying bills, selling or managing property, operating a business. If you grant authority over real property, the APP must be registered with the Land Titles Office ($181 fee).

Lifestyle — decisions about where you live, your daily routine, social activities, and personal care arrangements.

Healthcare — consenting to or refusing medical treatment on your behalf when you cannot make decisions yourself. This is the authority that activates in hospital settings.

You can appoint one person for all three areas, or split authority among different people. Splitting is common — you might trust your spouse for healthcare decisions but want your accountant daughter handling finances.

Who Can Be Appointed

An APP can appoint:

• An individual who is at least 18 years old
• A licensed trustee company
• The Public Trustee
• The Public Guardian

An individual under 18 can also be named, but the appointment has no effect until they turn 18. A person should be willing and able to carry out the role. For health care decisions, a person paid to support the maker in a commercial capacity cannot be the health care decision-maker; a family member or friend is not excluded merely because they receive a Commonwealth carer payment.

How the Appointment Works

The appointment is part of the Advance Personal Plan form. You name the person, specify their authority (financial, lifestyle, healthcare, or any combination), and can add conditions or limitations.

You can appoint multiple decision-makers for the same area. If you do, you must specify whether they act jointly (must agree on every decision), severally (each can act independently), or jointly and severally (they may act together or independently, but should agree).

Joint appointments create a practical risk in the NT: if one decision-maker is interstate or unreachable — common given the Territory's transient workforce — every decision is paralysed until both are available. Several appointments avoid this bottleneck.

When Authority Activates

A decision-maker's authority under an APP only activates when the maker loses decision-making capacity for the relevant decision. A healthcare decision-maker has no authority while you can make your own medical choices. A financial decision-maker has no authority while you are managing your own finances competently.

The trigger is a clinical assessment by the treating healthcare provider (for healthcare decisions) or evidence of incapacity (for financial decisions). Capacity is decision-specific — you might lack capacity for complex financial decisions while retaining capacity for everyday healthcare choices.

Choosing the Right Person

The practical considerations that matter most in the NT context:

Geographic availability. The NT's remoteness means your decision-maker might need to engage with Darwin or Alice Springs hospitals, the Public Guardian and Trustee, or the Land Titles Office. Someone in Sydney can do much of this remotely, but face-to-face may be needed for property transactions at the LTO.

Willingness to advocate. Banks and clinical teams sometimes push back on decision-makers. Your person needs to be comfortable asserting their legal authority — presenting the APP, requesting specific treatments, or refusing interventions you have documented.

Understanding of your values. For healthcare decisions, this is the most important criterion. Your decision-maker will be asked to interpret your wishes in situations your APP may not have anticipated. They need to know how you think about medical care, risk, and quality of life.

Potential for conflict. Think about family dynamics. If appointing one child over another will create conflict, consider appointing them jointly or choosing someone outside the family entirely.

What Happens Without an Appointment

If you lose capacity without an APP, an NTCAT-appointed guardian with healthcare authority comes first if one exists. Otherwise, the statutory hierarchy under the Health Care Decision Making Act 2023 considers a relative recognised under Aboriginal or other customary law or tradition, then a spouse or de facto partner, a non-commercial carer, adult children, parents, siblings, or close friends in that order — each with a close and continuing relationship — and finally the Public Guardian.

For financial decisions without an APP, family members may need to apply to NTCAT for a financial management order — a time-consuming and sometimes adversarial process.

The Privacy Problem

If you appoint a single decision-maker for both financial and healthcare matters in one combined APP, every institution that verifies the financial authority sees your intimate medical preferences. Banks have rejected combined APPs or delayed transactions because of uncertainty about the document's scope.

The practical solution: create two separate APPs — one financial, one healthcare/lifestyle. Both are valid under the Advance Personal Planning Act 2013.

Our Northern Territory Advance Directive & Living Will Kit includes a decision-maker worksheet to help you think through who to appoint, a comparison of joint versus several appointments, and step-by-step instructions for the split-document strategy.

See more Northern Territory guides →