Northern Territory of Australia v Yao

The Northern Territory of Australia, as the employer, and Ms. Yao, the worker, were the parties involved in this matter before the Full Court of the Supreme Court of the Northern Territory. The dispute concerned the onus of proof in relation to a defence raised by the employer that the worker's mental injury was excluded from compensation under section 3A(2) of the *Return to Work Act* because it arose from reasonable management action.

The legal issues before the Court were whether the employer or the worker bore the legal and evidential onus of proving that a mental injury was excluded by reason of section 3A(2) of the *Return to Work Act*. This provision operates to establish a general rule of liability for injury, while introducing an exclusion for mental injury caused by the specific element of reasonable management action.

The Court reasoned that, in conformity with general principles concerning the legal onus of proof, the employer bears the legal onus of establishing any assertion that an injury was the result of reasonable management action. This approach has been the practice in the Northern Territory. While other Australian jurisdictions have similar exclusionary provisions for injuries caused by reasonable administrative or disciplinary action, the approach to the legal onus in relation to these provisions is not uniform. The Court noted that the progenitor of section 3A was found in Commonwealth legislation, which has a substantial body of authority concerning its construction and operation, but no authority directly addressing the question of onus of proof in a judicial context. The Court observed that common law concepts of onus of proof are rarely appropriate for administrative tribunals exercising non-judicial power.

The Court determined that the employer carried the legal onus to prove the defence of reasonable management action. Both parties also carried an evidential onus in relation to this defence.