Finding out that a loved one’s will doesn’t reflect the person you knew can be deeply unsettling. Perhaps a will was rewritten shortly before death, cutting out children who were once close, or handing the bulk of an estate to a new acquaintance or carer. In these situations, Western Australian law allows the validity of a will to be challenged, not just its fairness, but whether it should stand at all.
This is different from a family provision claim, which accepts the will is valid but argues it didn’t adequately provide for someone. A validity challenge, by contrast, says the document itself shouldn’t be recognised as the deceased’s true will, because they lacked the mental capacity to make it, or because someone manipulated them into signing it.
Here’s what you need to know if you’re considering this path, and why speaking with a wills and estate lawyer early on can make all the difference.
What Makes a Will Legally Valid in WA?
Under the Wills Act 1970 (WA), a will must generally meet several formal requirements to be valid:
- It must be in writing.
- It must be signed by the will-maker (the testator), or by someone else in their presence and at their direction.
- The signature must be made or acknowledged in the presence of two witnesses, present at the same time.
- Both witnesses must then sign the will in the testator’s presence.
Beyond these formalities, the will-maker must have understood what they were doing, made the will freely, and genuinely intended its contents to reflect their wishes. A will that ticks every formal box can still be challenged if the person lacked the mental capacity to make it, or if someone else’s influence overpowered their own free will.
What Is Testamentary Capacity?
Testamentary capacity refers to the mental ability required to make a valid will. The long-standing legal test, drawn from the English case of Banks v Goodfellow, requires that the will-maker:
- Understood that they were making a will and what that means.
- Understood, in general terms, the nature and extent of their property.
- Was aware of the people who might reasonably expect to benefit from their estate (such as a spouse or children).
- Was not suffering from any delusion or disorder of the mind that distorted their sense of right and wrong in disposing of their property.
Capacity is assessed at the time the will was made. Someone can have good days and bad days, a diagnosis like dementia doesn’t automatically mean every will made afterward is invalid, but it does raise questions that need to be properly examined.
Warning Signs the Deceased May Have Lacked Capacity
Certain circumstances tend to raise red flags and warrant closer scrutiny, including:
- A diagnosis of dementia, Alzheimer’s, or another cognitive condition around the time the will was made.
- Sudden, significant changes to a long-standing will, especially late in life.
- Confusion about family members, assets, or personal affairs noted by doctors, carers, or family.
- The will being made in hospital, in palliative care, or shortly before death.
- A solicitor or witness who wasn’t a regular, independent professional, or who left little record of assessing capacity.
None of these signs is conclusive on its own, but together they can support a case for further investigation.
What Counts as Undue Influence?
Undue influence goes a step further than persuasion. Australian courts distinguish between someone legitimately advocating for their own interests and someone coercing a vulnerable person into a will they wouldn’t otherwise have made. For a challenge to succeed, there generally needs to be evidence of actual coercion, not mere suggestion, encouragement, or emotional pressure of the ordinary kind.
Undue influence often arises where there’s a significant imbalance of power: an elderly, isolated, or dependent person and a carer, new partner, or family member who controls their day-to-day life. It frequently overlaps with diminished capacity, since a person with reduced mental resilience is more susceptible to pressure. Because of this overlap, undue influence is rarely argued alone, it’s usually raised alongside a capacity challenge.
What Evidence Might Be Needed?
Because undue influence leaves no medical paper trail, and capacity issues can be subtle, building a case usually draws on multiple sources of evidence, such as:
- Medical records – GP notes, specialist assessments, hospital records, and any cognitive testing around the time the will was made.
- The file of the solicitor who drafted the will – including their notes on capacity, instructions taken directly from the testator, and whether they met with the testator alone.
- Witness statements – from family, friends, carers, or neighbours who observed the testator’s mental state or the behaviour of the person alleged to have exerted influence.
- Financial records – unusual withdrawals, changes to powers of attorney, or new dependency arrangements around the time of the will.
- Correspondence – emails, letters, or messages suggesting pressure, isolation from family, or control over the testator’s affairs.
The burden of proving lack of capacity or undue influence rests with the person bringing the challenge, so gathering solid, well-documented evidence early is essential.
Who Can Challenge a Will’s Validity in WA?
Unlike a family provision claim, which is restricted to specific categories of eligible people, a challenge to the validity of a will is generally open to anyone with a genuine interest in the outcome of the estate. This typically includes:
- Beneficiaries under the will being challenged.
- Beneficiaries under an earlier will who would benefit if the later will is found invalid.
- People who would inherit under the rules of intestacy if there were no valid will at all.
Time Limits: Why You Should Act Quickly
There’s no fixed statutory deadline for challenging the validity of a will on grounds of capacity or undue influence, unlike the strict six-month time limit that applies to family provision claims under the Family Provision Act 1972 (WA), which runs from the date probate is granted.
That said, delay can seriously undermine a validity challenge. Once probate is granted, an executor can begin distributing the estate, and unwinding those distributions later is far more difficult and costly. The most effective way to challenge a will is often to act before probate is granted, by lodging a caveat with the Supreme Court of WA. A caveat prevents a grant of probate from being issued until the concerns are resolved, buying time to investigate and gather evidence properly.
Acting quickly also means witnesses’ memories are fresher, medical records are easier to obtain, and the estate hasn’t yet been dispersed among beneficiaries.
What Happens If the Will Is Declared Invalid?
If a court finds that a will is invalid, because the testator lacked capacity, was unduly influenced, or the will otherwise fails to meet legal requirements, the estate doesn’t simply stay frozen. Instead:
- An earlier valid will, if one exists, is generally reinstated and governs the distribution of the estate.
- If there’s no earlier valid will, the estate is distributed according to the rules of intestacy under WA law, which set out a fixed order of who inherits (typically starting with a spouse or de facto partner, then children).
A successful challenge can significantly reshape who receives what, which is exactly why these matters are so often contested, and why they benefit from careful, well-supported legal argument.
Getting Advice Early
Challenges based on capacity or undue influence are among the most fact-intensive and evidence-heavy disputes in estate law. They often turn on medical opinion, solicitor’s notes, and circumstantial evidence pieced together carefully. If you have concerns about a loved one’s will, speaking with a WA wills and estates lawyer as early as possible gives you the best chance of protecting the evidence you’ll need and, if appropriate, lodging a caveat before the estate is distributed.
This article is general information only and does not constitute legal advice. Every estate dispute turns on its own facts, and outcomes depend on the specific evidence available. If you’re considering challenging a will in Western Australia, seek advice from a qualified wills and estates lawyer about your circumstances.
