I do not agree that Australia has the power to impose airspace limitations on Australian aircraft in international airspace ...
The Commonwealth of Australia can impose any airspace limitations it likes, on any aircraft with Australian nationality, anywhere in the universe.
If the Commmonwealth can, as it does now, validly prohibit Australian aircraft from operating commercially inside
or outside Australian territory, without an AOC issued by CASA, the Commonwealth can declare a Romeo or other airspace outside Australian territory and it, too, will be binding on Australian aircraft.
You can test it though. Find some of this extra-territorial airspace in an Australian aircraft, bust it, and do a Darryl Kerrigan...
