"The states can refer powers to the federal Parliament but does the federal Parliament have to accept?"

Thanks for your question. Section 51(xxxvii) of the Australian Constitution says states can refer—give—the federal Parliament some of their law-making powers. This transfer of power requires both the state and the federal parliaments to pass bills and is usually agreed to by governments before any bills surrendering or accepting the powers are introduced. However—in theory—the federal Parliament could refuse to pass a bill accepting the referral.

An example of a referral is from 2002 when each of the states passed laws allowing the Australian Parliament to pass the Criminal Code Amendment (Terrorism) Act (2003). The referring acts included the condition that the Act could not be amended—changed—without the agreement of the states.

diagram to help explain The states can refer powers to the federal Parliament but does the federal Parliament have to accept?