Undue Influence vs Lack of Testamentary Capacity: What's the Difference?

The core difference

Three questions are often mixed together and should be kept apart:

• Capacity. Could this will-maker make the testamentary decision at all?
• Knowledge and approval. Did the will-maker know and approve the contents of this document?
• Undue influence. Did another person coerce the will-maker so that the document records someone else’s wishes?

Answering “yes” to one says nothing about the others. A fully capable will-maker can be coerced; a profoundly impaired one may have been left entirely alone.

Comparison at a glance

Testamentary capacity in outline

Capacity is assessed by reference to Banks v Goodfellow (1870) LR 5 QB 549, which remains the governing test in Victoria. In broad terms the will-maker must understand the nature and effect of making a will, be aware in general terms of the extent of their property, appreciate and be able to evaluate the claims of those who might expect to benefit, and not be affected by a disorder of the mind or delusion that influences the disposition.

Capacity is specific to the document and the occasion. It is a legal conclusion drawn from the whole of the evidence, not a medical diagnosis. For the full analysis, the functions and the medical evidence that actually assists, see what testamentary capacity means in Victoria and challenging a will for lack of testamentary capacity.

Capacity and the relevant time

The ordinary rule is that capacity is assessed at the relevant time of will-making. That is usually execution, but it is not an exceptionless rule.

Under the limited principle in Parker v Felgate (1883) 8 PD 171, instructions given while the will-maker had capacity may support a will executed later, when their condition has declined. The will must give effect to those instructions, and at execution the will-maker must understand that the document gives effect to the earlier instructions and is being signed as their will. The principle is fact-sensitive, turns on careful evidence about the instructions and the execution, and must not be treated as a broad way around incapacity. Its application in a particular estate is a matter for advice; the doctrine is developed further in the capacity article.

Knowledge and approval

Knowledge and approval is a distinct requirement. Capacity asks whether the will-maker could make a valid testamentary decision. Knowledge and approval asks whether they in fact knew and approved the contents of the instrument put forward. Due execution and capacity do not necessarily dispose of it.

Matters that may be relevant — without being determinative — include a beneficiary’s involvement in instructions, unusual drafting, an inability to read the document, language or communication difficulties, haste, and an unexplained departure from earlier wills. Where the circumstances excite the Court’s suspicion, the propounder must dispel it with affirmative and cogent evidence. The detailed treatment sits in undue influence and suspicious circumstances.

Probate undue influence

Undue influence in the probate jurisdiction requires actual coercion: pressure of a kind and degree that overbore the will-maker’s free volition so that the document does not represent their own testamentary intentions. The classic formulation in Wingrove v Wingrove (1885) 11 PD 81 is applied in Australia (see, for example, Nicholson v Knaggs [2009] VSC 64; Boyse v Rossborough (1857) 6 HL Cas 2). Persuasion, advice, appeals to affection, moral pressure and mere opportunity are not coercion.

There is no presumption of undue influence in probate equivalent to the equitable presumptions that can arise in some lifetime transactions. The party alleging probate undue influence carries that burden throughout. The propounder does not acquire a burden of disproving coercion merely because suspicious circumstances exist.

Proving coercion by inference

Coercion rarely happens in front of witnesses, so direct evidence is uncommon. Australian courts accept that undue influence may be established by inference from cumulative circumstantial evidence. The approach taken in Nicholson v Knaggs is to evaluate the evidence as a whole rather than dismissing each strand in isolation, and to ask whether the alleged inference is more probable than not.

That is a real but disciplined path to proof:

• opportunity, dependency, a beneficiary’s involvement and an unusual disposition are none of them automatically sufficient merely because they exist;
• but they are not legally irrelevant either — taken together with other evidence they may support an inference of coercion;
• a weak, ill or dependent will-maker may require far less pressure before their free will is overborne, although vulnerability is not itself proof that pressure was applied;
• the standard remains the balance of probabilities, with the cogency of the evidence assessed having regard to the gravity of the allegation (see Evidence Act 2008 (Vic) s 140).

What does not follow is that unequal provision proves wrongdoing: will-makers may make unequal, even surprising, wills. Coercion indicators and the conduct of proceedings are covered in the dedicated undue influence article.

Vulnerability is not incapacity, and not coercion

This is the single most common source of confusion in estate disputes. Cognitive impairment, frailty, dependency, isolation and illness are often relevant context across several grounds. They are not, by themselves, proof of incapacity, of want of knowledge and approval, or of undue influence.

A will-maker may have capacity and still be coerced. A will-maker may lack capacity with nobody influencing them at all. A diminished ability to resist pressure may affect the factual assessment of what pressure would have been enough — but it does not remove the need to prove that coercion actually occurred.

Burdens, presumptions and suspicious circumstances

Loose talk about “the onus shifting” causes real problems. The position is better stated in steps:

1. The propounder bears the ultimate legal burden of establishing due execution, testamentary capacity, and knowledge and approval.
2. Where the will is rational on its face and duly executed, ordinary presumptions assist the propounder, and that may be enough if nothing displaces them.
3. If the challenger raises a real doubt on the evidence about capacity, those presumptions no longer carry the propounder, who must then establish capacity affirmatively (Kantor v Vosahlo [2004] VSCA 235, applying Worth v Clasohm).
4. Where suspicious circumstances are established, the propounder must dispel the Court’s suspicion by affirmative and cogent evidence. What rises is the evidentiary demand; the legal burden was always the propounder’s.
5. Suspicious circumstances principally engage knowledge and approval and the intensity of the Court’s scrutiny. They are not themselves a finding of coercion.
6. The party alleging probate undue influence bears that burden from start to finish, whatever the state of the capacity or knowledge and approval issues.

Fraud, forgery and fraudulent calumny

These are separate grounds again, and they must be distinctly alleged and proved on evidence appropriate to the seriousness of the allegation.

• Forgery concerns whether the signature or the testamentary instrument is genuine at all.
• Probate fraud is not limited to a single false statement made to the will-maker; it concerns dishonest conduct that induced the testamentary disposition.
• Fraudulent calumny concerns deliberately poisoning the will-maker’s mind against a potential beneficiary through false allegations, intended to cause exclusion or reduced provision. It is distinct from coercion, from innocent misinformation, from ordinary family disagreement and from genuinely held criticism.

The scope of fraudulent calumny in Victoria is still developing. In Re the estate of Iovenitti [2026] VSC 106 the Court declined to dispose of a challenge summarily where the grounds raised, including fraud, disclosed a case for investigation. Whether such a ground is available and arguable on particular facts is a question for advice.

Family provision is a different claim

A family provision claim under Part IV of the Administration and Probate Act 1958 (Vic) is not an alternative label for the same case. It assumes the operative distribution is otherwise legally effective and asks the Court to order further provision for an eligible person, rather than to invalidate the will.

Validity proceedings and family provision claims have different elements, procedures, remedies and timing. Protective or alternative claims sometimes have to be considered together — a challenger may need to investigate validity while protecting a family provision position — but they remain distinct causes of action. The six-month family provision period is not a universal deadline for a probate validity challenge, and specialist advice is needed so that one proceeding or limitation issue is not lost while the other is investigated. Eligibility, timing and quantum are dealt with in family provision claims in Victoria.

Which issue do the facts raise?

How the same evidence works differently

Much of the material in an estate dispute is relevant to more than one question, but it does different work on each.

Several practical points follow. Testamentary capacity is a legal conclusion, not a medical diagnosis, so useful medical evidence addresses the Banks v Goodfellow functions rather than merely naming a condition. Contemporaneous evidence usually carries particular weight, and retrospective expert opinion formed years later has real limitations. Solicitor and lay evidence may be decisive. Evidence from interested witnesses is not automatically excluded, but weight and credibility matter. And the same fact may support different inferences: it must not be relabelled as proof of every ground at once.

The Supreme Court of Victoria publishes current Probate Office affidavit-of-testamentary-capacity templates for a medical practitioner, for the lawyer who prepared and witnessed the will, and for another person who knew the deceased well (linked below). They are procedural resources — they do not decide a contested capacity question. For the expert-evidence detail, see medical evidence in testamentary capacity disputes.

Procedure, urgency and remedies

Before a grant. A probate caveat may preserve the position by requiring the Court to deal with the issues before any grant issues. It requires a proper probate interest and proper grounds, and it is not a general device for negotiating a larger inheritance. The mechanics, warning-off procedure and risks are set out in probate caveats in Victoria.

After a grant. Revocation or recall of the grant may be sought in an appropriate case, but distribution and third-party dealings can complicate the relief available. See challenging a will after probate has been granted.

Timing. There is no single fixed limitation period that governs every will-validity challenge. Delay nonetheless carries serious evidentiary, procedural and costs risk, and depending on the relief sought it may engage discretionary or limitation considerations. That is different again from the six-month period that applies to family provision claims.

Remedies. Depending on the ground established, the Court may:

• refuse a grant, or revoke a grant already made;
• pronounce for or against a testamentary instrument;
• admit an earlier valid will to probate;
• leave the estate to be distributed on intestacy if no valid will governs;
• admit only a valid part of a document where severance is legally available on the facts.

Family provision is different in kind: it changes the distribution without declaring the will invalid.

Executors, beneficiaries and preserving evidence

• Do not distribute while a genuine validity dispute is unresolved.
• Secure the original will and any earlier testamentary documents.
• Preserve the drafting file, instructions, drafts and correspondence.
• Identify the relevant medical and care records, and who holds them.
• Record the names of the execution witnesses and of anyone who saw the will-maker around that time.
• Preserve messages and documents lawfully. Do not access another person’s accounts, phone or devices without authority.
• Do not coach witnesses or help family members construct a common account.
• Find out whether a grant has already issued.
• Separate dissatisfaction with the provision made from evidence that the will is invalid — they lead to different claims.
• Obtain advice promptly about caveats, evidence, family provision timing and costs exposure.

Access to a solicitor’s file or to medical records cannot be promised: it ordinarily depends on entitlement, consent, a lawful request, subpoena or an order for production, and privilege and privacy questions may arise.

Costs in outline

Probate validity litigation is ordinarily subject to conventional costs principles. The estate does not automatically pay every party’s costs. Conduct, whether a party had reasonable grounds, whether the deceased’s own conduct caused the litigation, and the outcome may all affect costs. Filing a caveat or making serious allegations without a proper basis can create real adverse costs exposure. The detail is in costs in contested will proceedings.

Related reading

• Challenging a will for lack of testamentary capacity — the full capacity challenge, evidence and procedure.
• Undue influence and suspicious circumstances — coercion indicators and circumstantial proof.
• Can a person with dementia make a valid will? — diagnosis, fluctuation and the legal test.
• Mediation in estate litigation — how most estate disputes are actually resolved.

Frequently asked questions

Official sources

• Administration and Probate Act 1958 (Vic) — current in-force version, including Part IV family provision
• Supreme Court (Administration and Probate) Rules 2023 (Vic) — probate procedure, including caveats
• Evidence Act 2008 (Vic) — s 140, the civil standard and the gravity of the allegation
• Supreme Court of Victoria — wills and probate guidance
• Probate Office — affidavit of testamentary capacity by a medical practitioner
• Probate Office — affidavit of testamentary capacity by the lawyer who prepared and witnessed the will
• Probate Office — affidavit of testamentary capacity by a person other than a medical practitioner or lawyer
• Kantor v Vosahlo [2004] VSCA 235 — onus of proof and careful scrutiny
• Nicholson v Knaggs [2009] VSC 64 — circumstantial evidence, standard of proof and severance

How Parke Lawyers can help

Most of the value in an estate dispute is created early, when the evidence still exists and the grounds are still being identified. Choosing the wrong label — or filing a caveat without proper grounds — is expensive in both costs and credibility.

Parke Lawyers’ estate litigation and TFM claims team advises executors, beneficiaries and excluded family members on which grounds the evidence genuinely supports, how to preserve and obtain that evidence lawfully, whether a caveat or a family provision claim is the right step, and the realistic costs of each path.