It is necessary, however, to understand what is meant by “jurisdictional error” under the general law and the consequences that follow from a decision-maker making such an error. As was said in Craig v South Australia, if an administrative tribunal (like the Tribunal)
“falls into an error of law which causes it to identify a wrong issue, to ask itself a wrong question, to ignore relevant material, to rely on irrelevant material or, at least in some circumstances, to make an erroneous finding or to reach a mistaken conclusion, and the tribunal’s exercise or purported exercise of power is thereby affected, it exceeds its authority or powers. Such an error of law is jurisdictional error which will invalidate any order or decision of the tribunal which reflects it.”
“Jurisdictional error” can thus be seen to embrace a number of different kinds of error, the list of which, in the passage cited from Craig, is not exhaustive. Those different kinds of error may well overlap. The circumstances of a particular case may permit more than one characterisation of the error identified, for example, as the decision-maker both asking the wrong question and ignoring relevant material. What is important, however, is that identifying a wrong issue, asking a wrong question, ignoring relevant material or relying on irrelevant material in a way that affects the exercise of power is to make an error of law. Further, doing so results in the decision-maker exceeding the authority or powers given by the relevant statute. In other words, if an error of those types is made, the decision-maker did not have authority to make the decision that was made; he or she did not have jurisdiction to make it. Nothing in the Act suggests that the Tribunal is given authority to authoritatively determine questions of law or to make a decision otherwise than in accordance with the law.