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Legal concepts
Breach of duty is the point in a professional negligence claim where a professional’s conduct is measured against what a reasonably competent practitioner in their field would have done. It is not about a bad result. It is about whether the professional fell below the standard the law requires — and whether that failure caused your loss.
When something goes wrong with professional advice or treatment, most people’s first instinct is to wonder whether they were let down — or whether it was just an unfortunate outcome. That distinction is exactly what breach of duty is designed to resolve. It is one of the most contested elements in any professional negligence claim, and understanding it clearly matters before you decide whether to act.
The legal standard
In a professional negligence claim, four things generally need to be established: duty of care, breach of that duty, causation, and loss and damage. Duty of care — the legal obligation a professional owes you when you engage their services — is rarely the battleground. In most professional relationships, it exists almost automatically.
Breach is different. This is where claims are won and lost.
Breach of duty asks a specific question: did the professional’s conduct fall below the standard of care expected of a reasonably competent practitioner in their field? Not the best in the country. Not a specialist with thirty years of experience. A competent, ordinarily skilled professional doing their job properly.
If the answer is yes — and if that failure caused you measurable loss — there may be a claim worth pursuing. If the professional made a difficult call that any reasonable colleague might have made the same way, that is a different matter entirely.
The distinction between a bad outcome and a professional failure is not always obvious from the outside. That is precisely why breach of duty cases almost always require expert evidence from someone practising in the same field.
The statutory framework
Australian courts do not rely on gut feeling. The assessment of breach is structured — and in most states, it follows a statutory framework.
Section 5B of the Civil Liability Act 2002 (NSW) sets out the test courts apply. Equivalent provisions exist in other states: s 48 of the Wrongs Act 1958 (VIC) and s 9 of the Civil Liability Act 2003 (QLD) follow the same logic. Under these provisions, a defendant is not liable in negligence unless the risk of harm was foreseeable, not insignificant, and a reasonable person in their position would have taken precautions.
The legislation then directs courts to weigh four factors when deciding whether a reasonable person would have acted differently:
A remote or highly unlikely risk carries less weight than a foreseeable one. Courts ask how likely it was that harm would occur if the professional took no precaution against the risk in question.
The more severe the potential consequence, the greater the obligation to guard against it. A risk that could result in permanent disability or financial ruin demands more precaution than one with minor consequences.
Courts consider what it would have actually cost the professional — in time, money, or disruption — to avoid the risk. A precaution that was simple and low-cost weighs more heavily in favour of taking it.
Some professional activities carry inherent risk, and the law does not expect professionals to eliminate all possibility of harm. Emergency surgery is assessed differently from an elective procedure. The court weighs the value of the professional's activity against the risk it created.
This is a balancing exercise. Courts are not looking for perfection. They are asking whether this professional, on the evidence, did what a competent practitioner would reasonably have done in the same circumstances.
Rogers v Whitaker and beyond
The benchmark in Australian law is the reasonable practitioner — not the most cautious, not the most brilliant, but someone with ordinary competence in the relevant field acting with reasonable care.
This standard was firmly established by the High Court in Rogers v Whitaker (1992) 175 CLR 479. The majority rejected the English Bolam test — which had allowed professionals to escape liability simply by pointing to a body of peers who would have done the same thing — and held that Australian courts are not bound by what other professionals would have accepted as standard practice. The ultimate question of whether conduct was reasonable is one for the court, not the profession.
This matters practically. A professional cannot avoid a finding of breach simply by demonstrating that others in their field routinely did the same thing. If that practice was itself unreasonable — if it exposed patients, clients, or customers to foreseeable and preventable harm — the court may still find against them.
Expert evidence remains essential. Courts need to understand what competent professionals in the relevant field actually do, what they would have advised, and what the accepted range of practice looks like. Without expert evidence, it is very difficult to establish where the reasonable practitioner standard sits.
What it looks like in real life
Understanding breach becomes easier when you see what it looks like across different professions. These are the kinds of conduct that, depending on the circumstances, may amount to a breach of duty:
A lawyer handling a personal injury claim fails to file court documents before the limitation period expires. The client's right to sue is permanently lost — not because the claim lacked merit, but because the deadline was missed.
A physician diagnoses a patient's recurring symptoms as stress-related without ordering investigations that the standard of care required. The underlying condition is found eighteen months later, by which point treatment options have narrowed significantly.
An adviser places a client's retirement savings into a high-risk investment vehicle without conducting adequate risk assessment or disclosing the product's speculative nature. The investment fails.
A tax accountant misapplies a deduction across multiple years of returns. The ATO issues amended assessments, penalties, and interest — all of which could have been avoided with competent advice.
A certifier signs off on a residential construction that contains a significant structural defect. The defect was identifiable during inspection and a competent certifier would have flagged it.
A pharmacist dispenses the wrong medication or the wrong dosage without checking the prescription or flagging a known drug interaction with the patient's existing medication.
None of these scenarios guarantee a successful claim. Each depends on the specific facts, the applicable standard of care at the time, and whether the breach caused the loss. But they illustrate what breach of duty actually looks like when it arises.
Setting the record straight
This is worth being direct about, because people sometimes arrive at legal advice expecting a claim that the evidence will not support.
Medicine, law, finance, and engineering all involve judgment calls under uncertainty. A competent professional can do everything right and still have things go wrong. The law does not impose liability for that.
If a reasonable practitioner, faced with the same information at the same time, might have made the same call — even if that call turned out to be wrong — that is not a breach of duty. Hindsight does not change the standard that applied at the time.
Poor communication or a relationship breakdown with a professional does not constitute breach. Being unhappy with how a professional handled your matter — even if that unhappiness is completely justified — is not the same as them falling below the legal standard of care.
The four-element framework
Breach does not stand alone. It sits within the four-element framework that underpins every professional negligence claim:
Even where breach is clearly established, the claim still depends on causation — the direct link between the professional’s failure and the loss you suffered. A lawyer who missed a filing deadline may have breached their duty, but if the underlying case had no prospects of success, the breach may not have caused a recoverable loss.
That connection — between what the professional did wrong and what it actually cost you — is often where professional negligence claims become complex. Understanding both elements is essential before assessing whether a claim is viable.
In most Australian states, professional negligence claims must be commenced within three years of the date you became aware — or should reasonably have become aware — of the negligence. Limitation periods vary: general claims in Victoria, Western Australia, and Tasmania may attract a six-year period. Missing this deadline can permanently extinguish your right to claim. If you are unsure whether your limitation period is still open, contact our team for a free assessment as soon as possible.
Case law
Maree Whitaker sought treatment from Dr Christopher Rogers to restore sight in her right eye, which had been blind since childhood. Dr Rogers operated without warning her of a small but known risk that the procedure could trigger sympathetic ophthalmia in her healthy left eye. It did. She lost almost all vision in that eye.
The High Court found that Dr Rogers had breached his duty by failing to disclose a risk the patient had a right to know about — regardless of whether other surgeons would have mentioned it. The decision fundamentally reshaped the standard of informed consent in Australian medical negligence and confirmed that professional custom is not the final word on what the law requires. Read more: Rogers v Whitaker explained.
Mr Naxakis was admitted to hospital following complaints of severe headaches. Medical staff discharged him without conducting a CT scan or angiogram. He suffered a ruptured cerebral aneurysm shortly afterward, leaving him permanently disabled.
The High Court considered both breach and causation in detail. The case reinforced that the reasonable practitioner standard requires active and appropriate clinical investigation where the symptoms warrant it, and that a failure to investigate — rather than a failure to treat — can itself constitute breach of duty.
While not a professional negligence case in the traditional sense, Vairy is significant for its detailed application of the s 5B balancing exercise. The High Court examined the probability of harm, the gravity of the consequences, and the burden of precautions — factors directly applicable to how courts assess breach across all negligence matters, including those involving professionals. It is regularly cited when courts are working through whether a defendant took reasonable precautions.
Breach is a legal question, but it starts with a factual one: what did the professional actually do, and what should they have done instead? Our experienced legal team can assess your situation in a free, confidential evaluation — no obligation, no pressure, no upfront cost.
Common questions
Duty of care is the legal obligation a professional owes you — it arises from the professional relationship itself and is rarely disputed. Breach is whether the professional lived up to that obligation. Think of duty as the standard being set and breach as the question of whether the professional met it. Both need to be established for a negligence claim to succeed, but in most professional negligence cases it is breach — not duty — that is contested.
Courts apply the reasonable practitioner standard — asking whether a competent professional of ordinary skill in the same field would have acted differently. Under the Civil Liability Acts that operate across Australian states, courts also weigh the probability of harm, its likely seriousness, the burden of precautions, and the social utility of the professional’s conduct. Expert evidence from practitioners in the same field is almost always required to help the court understand where that standard sits.
Yes. Since the High Court’s decision in Rogers v Whitaker, Australian courts are not bound by what the profession itself regards as acceptable practice. If a widespread practice nonetheless exposed clients or patients to foreseeable and preventable harm, a court may find that the practice itself fell below the legal standard of care. Professional custom is relevant evidence, but it is not a complete defence.
In most professional negligence cases, yes. Courts rely on expert evidence to understand what a reasonably competent practitioner in the relevant field would have done. Without it, there is no reliable basis for the court to assess whether the defendant’s conduct fell below the standard. Identifying and briefing the right expert is one of the first practical steps in building a breach of duty case.
An honest mistake is not automatically a breach of duty. If a reasonable practitioner could have made the same mistake given the same information at the same time, there may be no breach. The law does not require professionals to be infallible — it requires them to exercise reasonable care and skill. Where an honest mistake reflects a failure to apply that care — where a competent professional would not have made the same error — it may well amount to breach.
Our goal is to help people in the best way possible. this is a basic principle in every case and cause for success. contact us today for a free consultation.
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