When a Plaintiff's injury is exacerbated by an unrelated event to that which formed the basis of the claim, how does MAS determine whether the event was indeed unrelated? The case of Smith v Insurance Australia Ltd examines the MAS Review Panel's role in determining complex issues of causation when a Plaintiff's injury has been worsened subsequent to the accident which formed the basis of a CTP claim.

Judgment date: 30 October 2018 Citation: Smith v Insurance Australia Ltd [2018] NSWSC 1606 Jurisdiction: Supreme Court of New South Wales


  • The role of a Medical Review Panel is to hand down a decision on the medical issue referred to it by applying its own medical experience and expertise, as opposed to adjudicating a dispute between the parties based on their medical evidence;
  • When a further impairment is caused by an unrelated event to that which formed the basis of the Plaintiff's claim, clause 1.36 of the Motor Accident Permanent Impairment Guidelines is activated, provided the event was indeed unrelated, as opposed to being (for example) treatment or surgery for the original injury or condition.


The Plaintiff was involved in a motor vehicle accident in which he alleges to have sustained both physical injuries and psychiatric sequelae. Although both physical and psychiatric injuries were referred to the Medical Assessment Service ('MAS') in light of a dispute between the parties regarding the Plaintiff's entitlement to damages for whole person impairment, this case only concerns the assessment of the psychiatric sequelae.

Initially upon referral to MAS, Assessor Mason issued a Certificate finding the psychiatric sequelae amounted to 14% whole person impairment. The Insurer challenged this finding by seeking a further medical assessment and subsequently, Assessor Prior reduced the Plaintiff's whole person impairment yielded by the Post-Traumatic Stress Disorder and exacerbation of Major Depressive Disorder to 7%. The Plaintiff sought a review of Assessor Prior's determination, and the Medical Review Panel found the psychiatric symptoms amounted to 8% whole person impairment. The finding of 8% whole person impairment was made after deducting 9% whole person impairment from an overall finding of 17% whole person impairment, on account of unrelated psychiatric symptoms stemming from the death of the Plaintiff's brother-in-law subsequent to the motor vehicle accident.

The Plaintiff sought prerogative relief in relation to the Medical Review Panel's decision on the basis that the Certificate contained both jurisdictional errors and errors on the face of the record.


His Honour Justice Davies turned to two relevant cases in considering the Plaintiff's unrelated subsequent psychiatric symptoms, and making his determination.

Firstly, in the case of Allianz Australia Insurance Ltd v Motor Accidents Authority of NSW [2011] NSWSC 102 ('Allianz' ), Hidden J accepted the Insurer's submission that an 'unrelated' injury or condition is not the same as an impairment being increased due to further treatment or surgery for the injury or condition. In that case, the Plaintiff's condition was exacerbated by a wholly unrelated event, being a second accident, and his Honour accepted this to be an 'unrelated' event leading to further injury.

Secondly, his Honour referred to GIO General Limited v Smith ('Smith' ) (relied upon by the Insurer) for guidance in relation to interpretation of an 'unrelated' injury or condition. His Honour Justice Hoeben indicated that the term 'unrelated injury or condition' refers to the event causing the subsequent injury, rather than the medical description of the injury itself. This in turn effects Guideline 1.36, which a Review Panel would be required to take into consideration, as an injury to the same body part under this guideline would not be deemed unrelated, whereas an event would allow the guideline to be considered and applied. Hoeben J therefore distinguished between the event and injury and its effect on the relevant guidelines.

Taking into account the principles in Allianz and Smith, Justice Davies determined the Medical Review Panel did not use the wrong test of causation, and it made clear findings of fact in relation to how the unrelated event, being the death of the Plaintiff's brother-in-law, worsened the Plaintiff's condition. Further, there was no denial of procedural fairness afforded to the Plaintiff in the Medical Review Panel's conduct and final determination.

Justice Davies ultimately found in favour of the Insurer and dismissed the Plaintiff's Summons, with an order for the Plaintiff to pay the Insurer's costs.

Why this case is important

This decision sets a strong precedent for an Insurer not bearing full culpability in circumstances where a Plaintiff is injured by a separate and unrelated event to the claim, even if the same bodily region or condition is exacerbated.

The decision confirms the importance of investing in expert opinions and undertaking thorough investigations in circumstances where causation of an injury is multifaceted.