Administrative law is difficult to define, and we will not attempt to do so in an exact way. For most Australian scholars, administrative law might simply mean the parts of public law that do not include constitutional law – but many chapters of this book demonstrate that constitutional law and its consequences can never be entirely separated from administrative law. That said, administrative law can still be defined in part by reference to constitutional law. Constitutional law is largely concerned with the nature and scope of the powers held by each arm of government within the Constitution. Administrative law is all about what the agencies of the executive government (ministers, departments, agencies and the individual officials who work within these bodies) can and cannot do. More particularly, administrative law encompasses the different mechanisms and principles that enable people to question or challenge the decisions of these agencies of government.

While the courts play a significant role in these processes (principally through the exercise of their judicial review jurisdiction and, to a lesser extent, through their appellate jurisdiction over many other administrative decisions), they form only one part of the picture. A defining feature of administrative law is the important role played by non-judicial bodies, such as tribunals and Ombudsmen, who receive many more complaints than the courts. Another defining feature of administrative law is the different remedies offered by its different institutions.