https://www.theguardian.com/commentisfree/2017/jan/04/bob-hawkes-narrati...
I know how it can be done.
The States, under the Constitution, gave voluntarily give up land to the Commonwealth (such as Jervis Bay Territory).
"The Parliament of a State may surrender any part of the State to the Commonwealth; and upon such surrender, and the acceptance thereof by the Commonwealth, such part of the State shall become subject to the exclusive jurisdiction of the Commonwealth. "
(COMMONWEALTH OF AUSTRALIA CONSTITUTION ACT - SECT 111)
The rest I leave to your imagination.