Rix v Mahony

In *Rix v Mahony*, the New South Wales Court of Appeal considered an application to adduce further evidence on appeal. The applicant asserted that this evidence should have been presented to the judge in earlier proceedings and, if admitted, would have established a *res judicata* estoppel against the conclusions reached in the decision under appeal.

The primary legal issue before the Court of Appeal was whether the applicant's assertion correctly formulated the doctrine of *res judicata* in the context of an application to introduce new evidence on appeal. The Court was required to determine the appropriate principles governing the admission of further evidence in appellate proceedings and how those principles interacted with the doctrine of *res judicata*.

The Court of Appeal reasoned that the applicant's formulation of *res judicata* was incorrect. The doctrine of *res judicata* operates to prevent the relitigation of issues that have already been finally determined by a court of competent jurisdiction. The Court held that an application to adduce further evidence on appeal, particularly when it is argued to create an estoppel against a prior decision, must be assessed against the established rules for admitting such evidence, rather than through a misapplication of *res judicata*. The Court ultimately refused the application to adduce further evidence.