Challenging a Will for Lack of Testamentary Capacity in Victoria

What Is Testamentary Capacity?

Testamentary capacity is the legal test for whether a person is mentally capable of making a valid Will. The modern test still traces back to the 1870 English case of Banks v Goodfellow and continues to be applied in Victoria. The Will-maker must understand the nature and effect of a Will, the general extent of their property, the people who might reasonably expect to benefit, and must be free from any disorder of the mind that distorts their decisions.

Capacity is assessed at the moment the Will is signed. A person can have capacity to make a Will even where they need help with day-to-day affairs, and conversely a person who functions well in many areas may still lack the specific capacity required for a Will. For a fuller treatment, see our overview of testamentary capacity in Victoria.

When Can Capacity Become an Issue?

Capacity can arise as an issue in a wide range of circumstances. Some of the most common situations include:

• Dementia — Alzheimer's disease, vascular dementia and other forms of cognitive impairment are frequent triggers for a capacity challenge, particularly where the Will was made after diagnosis.
• Cognitive decline — even without a formal diagnosis, evidence of declining memory, confusion or poor decision-making in the lead-up to the Will can raise concerns.
• Serious illness — Wills made shortly before death, during hospitalisation, or while the Will-maker was acutely unwell are more vulnerable to challenge.
• Medication effects — strong analgesics, sedatives or psychiatric medications can affect cognition. The Court may consider whether the Will-maker was lucid at the time of signing.
• Unusual Will changes — a sudden departure from a long-standing pattern (for example, excluding a child of many years, or leaving everything to a new acquaintance) often prompts closer scrutiny, particularly if combined with cognitive concerns.
• Mental illness — conditions involving delusions or distorted perceptions can affect capacity where they are connected to the disposition of the estate.

None of these factors automatically invalidates a Will. They are warning signs that prompt closer inquiry into whether the legal test was met at the relevant time.

Does a Dementia Diagnosis Automatically Invalidate a Will?

No. A diagnosis of dementia — even moderate dementia — does not automatically prevent a person from making a valid Will in Victoria. Testamentary capacity is a legal test, not a medical one, and it focuses on what the Will-maker actually understood at the time of signing.

Many people with early-stage dementia retain sufficient capacity to make straightforward Wills. Capacity can also fluctuate, so a person who is confused one day may be lucid the next. The question for the Court is not "Was there a diagnosis?" but "Did the Will-maker meet the legal test at the time the Will was signed?".

For a more detailed discussion, see our article on whether a person with dementia make a valid Will in Victoria.

What Evidence Is Commonly Considered?

A capacity challenge is decided on the evidence available, much of which has to be reconstructed after the Will-maker has died. The most commonly considered material includes:

• Medical records — hospital admissions, discharge summaries, nursing notes and records of any cognitive assessments performed during treatment.
• GP records — often the most consistent source of information about the Will-maker's cognition and health over time, particularly entries close to the date the Will was signed.
• Specialist assessments — reports from geriatricians, neurologists, psychiatrists and neuropsychologists who have assessed the Will-maker clinically.
• Witness evidence — statements from family members, friends, carers and others about the Will-maker's behaviour, conversations and apparent understanding around the relevant time.
• Solicitor file notes — the notes of the solicitor who prepared the Will, including the questions asked, the instructions received and any capacity assessment carried out at the time.
• The Will itself — its terms, its rationality on its face, and how it compares with any earlier Will.

Why Medical Evidence Can Be Important

Of the categories above, medical evidence often plays a central role. Cognition is difficult to assess retrospectively, and lay witnesses can rarely speak to the underlying neurological or psychiatric picture. Contemporaneous medical records prepared close to the date of signing — particularly by a GP or specialist who knew the Will-maker — can be decisive.

Medical evidence is not always determinative. The Court considers it alongside the solicitor's file, the evidence of other witnesses and the broader factual circumstances. Strong medical evidence on one side does not always win the case if the broader picture points the other way.

What Happens If Capacity Is Disputed?

Where capacity is genuinely in issue, the practical response depends on the stage of the estate. In most cases, a capacity concern is raised before or during the probate application.

A person with sufficient interest in the estate — for example, a beneficiary under an earlier Will or a person entitled on intestacy — can take steps to put the Court on notice that the Will should not be admitted to probate without proof of capacity. This often involves a probate caveat and the gathering of medical and witness evidence. Depending on the strength of the material, the matter may be resolved by negotiation, mediation or contested proceedings.

A capacity challenge is a serious step and carries litigation risk on both sides. Early legal advice helps assess whether the evidence is likely to support a challenge before any formal action is taken.

Can a Court Declare a Will Invalid?

Yes. The Supreme Court of Victoria has jurisdiction to decide whether a Will is valid. If the Court is satisfied on the evidence that the Will-maker did not have testamentary capacity at the time of signing, it can refuse probate and declare the Will invalid.

If the Will is set aside, the estate is generally distributed under any earlier valid Will. If there is no earlier valid Will, the estate is distributed under Victoria's intestacy rules. The outcome on capacity can therefore have very significant practical consequences for the people who would (or would not) benefit under each alternative.

Practical Steps If You Have Concerns

Where capacity may be a live issue, the following practical steps can help protect the interests of beneficiaries, executors and the Will-maker:

1. Act early — concerns should be raised and investigated as soon as they arise, ideally before probate is granted.
2. Gather evidence — identify GP and specialist records, hospital admissions and any cognitive assessments. Note the names of witnesses who observed the Will-maker around the time the Will was signed.
3. Preserve documents — earlier Wills, correspondence with the solicitor who prepared the Will and any notes made by family members can all be relevant.
4. Avoid confrontation — capacity disputes are often emotionally charged. Direct accusations between family members can escalate the matter and reduce the prospects of negotiated resolution.
5. Consider professional executors — where conflict is likely, an independent executor or administrator can reduce friction during the dispute.
6. Seek legal advice early — an experienced estate disputes lawyer can assess the strength of the available evidence and the options for resolution, including alternatives to litigation. Capacity issues often intersect with Wills and estate planning and probate and estate administration and benefit from a coordinated approach.

Conclusion

Challenging a Will for lack of testamentary capacity is a significant step. The legal test is well established but its application is highly fact-sensitive, and outcomes depend on contemporaneous records, witness evidence and careful presentation of the medical material.

A diagnosis of dementia or another cognitive condition does not, by itself, invalidate a Will — but where there are real concerns that the Will-maker did not understand what they were doing, the Court has the power to refuse probate and set the Will aside.

If you are concerned about the validity of a Will on capacity grounds, or you are an executor facing a potential challenge, early legal advice is almost always the safest path.

Frequently Asked Questions