For example, certain decisions made by a delegate of the Minister for Immigration and Citizenship under the Migration Act 1958 may have been subject to merits review in the AAT.

The High Court long held that the Australian Constitution,[15] mandates a separation of powers between the executive, legislative and judicial branches of government.

The AAT had jurisdiction to review a number of decisions made under Commonwealth legislation, including in the areas of taxation, immigration, social security, industrial law, corporations and bankruptcy.

[19][20] Section 43(1) of the Administrative Appeals Tribunal Act stated that the AAT could exercise all the powers and discretions of the original decision maker.

The AAT's other members could be: Prior to the position of President being vacant, Justice Berna Collier was acting in that role following the resignation of Justice Fiona Meagher (who previously served as Deputy President and head of the National Disability Insurance Scheme Division).

Members of the Tribunal came from a range of backgrounds and included persons with expertise in accountancy, aviation, engineering, environmental science, law, medicine, pharmacology, military affairs, public administration, and taxation.

Members of the Tribunal who were legally qualified and had 5 years' standing, where authorised to do so, could exercise powers under a number of other Acts.

Presidential Members and Senior Members who are legally qualified and had 5 years' standing, could be appointed as approved examiners under the Proceeds of Crime Act 2002 The President and Deputy Presidents could be appointed as issuing authorities in relation to the making of continued preventative detention orders under the Criminal Code.