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LEGAL DOCTRINE HUB
When a professional gets it wrong — a solicitor who misses a deadline, a financial adviser who recommends unsuitable products, a doctor who fails to diagnose what should have been caught — the focus naturally falls on what they did. But Australian negligence law also asks a question about what you did after you found out.
The doctrine of mitigation of loss holds that a person who suffers harm as a result of someone else’s negligence has a legal duty to take reasonable steps to reduce that loss. It does not mean you must do everything possible, and it certainly does not mean a genuine claim is undermined. But it is a doctrine that every claimant needs to understand.
UNDERSTANDING THE DOCTRINE
In Australian negligence law, the duty to mitigate requires a claimant to take reasonable steps to reduce their loss once they become aware of the negligence. If a claimant fails to act reasonably, a court may reduce the damages awarded to reflect the loss that could have been avoided.
Here is what that looks like in real situations:
The consistent thread is reasonableness. Courts do not expect perfection. They ask whether the steps taken — or not taken — were what a reasonable person in the same circumstances would have done.
AUSTRALIAN LAW
The duty to mitigate is a long-standing principle of the common law, applied consistently in Australian courts. It does not appear in a single piece of legislation — rather, it operates as a limiting principle on the recovery of damages. A claimant is entitled to compensation for the loss caused by the negligence, but not for losses that a reasonable person in their position could have avoided.
The High Court’s approach in Malec v JC Hutton Pty Ltd (1990) 169 CLR 638 is instructive here. The Court confirmed that when assessing damages, courts engage in probabilistic reasoning about what would, or could, have happened had different steps been taken. This reasoning applies directly to mitigation — courts are essentially asking what would have happened to the claimant’s loss if they had acted differently after the negligence occurred.
Across Australian jurisdictions, the Civil Liability Acts interact with this common law principle. While those Acts primarily address contributory negligence and proportionate liability, the general framework reinforces that damages are assessed by reference to what was actually caused by the defendant’s negligence — not by losses the claimant had the means and opportunity to avoid.
The standard is always assessed by reference to the claimant’s actual circumstances — their financial position, access to professional advice, health, and the information available to them at the time. A claimant with limited resources is not held to the same standard as one with ready access to independent experts.
THE REASONABLENESS STANDARD
Courts look at the specific facts, not a theoretical checklist. But there are consistent factors that arise across professional negligence matters.
Financial practicality
Was the step financially feasible given what the claimant had available at the time? A claimant who had already exhausted their resources as a direct result of the negligence is not expected to fund expensive remediation out of their own pocket.
Access to independent advice
Did the claimant have access to independent professional advice? Did they act on it? A claimant who followed reasonable advice from an independent expert will generally be found to have discharged their duty to mitigate, even if that course of action did not fully arrest the loss.
Risk and hardship
The law does not require a claimant to take steps that would impose unreasonable risk, hardship, or expense on themselves. A patient is not obliged to undergo surgery to mitigate a loss if the surgery itself carries substantial risk.
Delay caused by the negligent professional
This is a point that is frequently overlooked. Where the claimant’s delay in taking steps was itself caused or prolonged by the negligent professional’s conduct — for example, a solicitor who failed to disclose the error, or a financial adviser who continued providing reassurances — Australian courts have limited the mitigation reduction accordingly. The claimant cannot be expected to act on information they were never given.
The claimant’s individual capacity
Courts consider the claimant’s personal circumstances — including their health, education, financial literacy, and the stress of the situation — in assessing what steps were reasonable. A claimant who was unwell or who lacked the knowledge to understand the significance of the error is judged by that context.
IMPACT ON YOUR CLAIM
Failing to mitigate does not defeat a claim. It may reduce the damages that are ultimately awarded, but a genuine negligence claim remains a genuine negligence claim regardless.
The practical consequence is this: where a court finds that some portion of the overall loss was avoidable, it will reduce the damages award to reflect only the loss actually caused by the negligence — not the additional loss that reasonable action would have prevented.
One of the most important points to understand is where the burden of proof sits. It is the defendant — the negligent professional or their insurer — who must prove that the claimant failed to mitigate. The claimant does not have to establish that they took every possible step. If the defendant cannot demonstrate that specific, reasonable steps were available and that the claimant unreasonably failed to take them, the mitigation argument will not succeed.
Many claimants assume they need to prove they did everything right after the negligence occurred. That is not the law. The onus falls on the other side to identify what should have been done and to establish that failing to do it was unreasonable in the circumstances.
CLAIM-SPECIFIC GUIDANCE
How the mitigation doctrine plays out will depend on the nature of the claim and the professional involved.
If your lawyer made an error — missed a limitation period, failed to advise of a crucial legal risk, or handled a transaction negligently — courts will consider whether you took reasonable steps once the error came to light. Engaging another solicitor promptly to assess the damage and explore available remedies is typically what a reasonable person would do. Where the error has already extinguished a legal right, the focus shifts to whether any residual steps could have produced a partial remedy.
Once a misdiagnosis is corrected, the question becomes whether the claimant followed through with appropriate treatment. Courts are not unsympathetic — a patient who has been failed by one medical professional may reasonably be anxious about further treatment. But an outright refusal of accessible and clinically recommended care, without good reason, may be scrutinised.
When unsuitable advice comes to light, did the claimant seek independent financial advice about how to limit ongoing losses? Did they liquidate positions that a reasonable investor, properly advised, would have exited? Continuing to hold assets — or making further investments on the same negligent advice — without any attempt to obtain independent guidance may attract scrutiny under the mitigation doctrine.
Where an accountant’s negligent advice triggers an ATO liability or penalty, courts will consider whether the claimant engaged a replacement adviser to correct the tax position and cooperated with ATO processes. Refusing to engage with the ATO, or delaying a resolution that could have limited penalties, may reduce the recoverable loss.
When a defect or design failure is identified, obtaining independent assessments and acting on reasonable remediation advice is generally expected. Allowing a defect to worsen without taking any steps to stabilise, rectify, or limit further damage may reduce the damages that can ultimately be recovered.
CONNECTED LEGAL PRINCIPLES
The mitigation doctrine does not operate in isolation. It sits alongside several other principles that affect how damages are assessed in professional negligence claims.
Contributory negligence and mitigation are frequently confused, but they arise at different points in time. Contributory negligence refers to conduct by the claimant that contributed to the original harm occurring. Mitigation relates to what the claimant did — or failed to do — after the harm. Both doctrines can reduce a damages award, but they are assessed separately and on different facts.
The mitigation doctrine only becomes relevant once causation has been established. If the professional’s negligence did not actually cause the loss, the question of mitigation does not arise. Causation and mitigation are distinct legal inquiries, and courts address them in sequence.
Even where a claimant has fully mitigated their loss, damages remain limited to losses that were a reasonably foreseeable consequence of the negligence. Losses that are too remote from the negligent act are not recoverable regardless of what steps the claimant took or did not take.
GET SPECIALIST GUIDANCE
If you are uncertain how the duty to mitigate applies to your situation — or concerned that steps you have taken, or failed to take, may affect a potential claim — the most reliable course is to speak with a specialist professional negligence lawyer.
Every case turns on its own facts. A free, confidential assessment will give you a much clearer picture of where you stand — with no obligation to proceed.
FREQUENTLY ASKED QUESTIONS
No. The standard is reasonableness, not perfection. Courts assess what a reasonable person in your specific circumstances would have done — taking into account your financial position, access to advice, health, and the information available to you at the time. It is also the defendant’s burden to prove you failed to mitigate, not yours to prove you did everything right.
Courts consider whether the claimant knew, or reasonably should have known, that steps were available and that failing to take them would increase the loss. Where the negligent professional concealed the error, delayed informing you, or continued to provide misleading reassurances, the court may limit any mitigation reduction accordingly. Ignorance caused by the professional’s own conduct is treated very differently from wilful inaction.
Potentially — but only if they can establish that the step was reasonable and accessible in your circumstances, and that taking it would have materially reduced the loss. That is their burden to discharge. Australian courts apply the reasonableness standard with regard to the claimant’s individual situation, including their health, financial position, and the information available to them at the time.
Contributory negligence concerns the claimant’s conduct that contributed to the original harm occurring — for example, ignoring an obvious risk or failing to follow clear professional instructions. Mitigation concerns what the claimant did after the harm occurred to limit its extent. Both can reduce a damages award, but they arise from different facts at different points in time. A claim can involve one, both, or neither.
See also: Legal Doctrine Hub | Compensation guide | Free case evaluation
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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