Can Australia claim to be a ‘post-colonial’ nation?
Historically, yes. In the eighteenth century England established penal colony at Sydney Cove because its jails were overflowing. These personnae non gratae were kept at a safe distance from the mother country (about 14,000 miles!) and alleviated the prisons back home. These labour camp convicts were put to work to produce and export much-needed flax and pine (used primarily in ship-building). England was also looking to establish a naval base in this area along the Eastern trade route. Such a place would also serve as a resourcing station for ships at sea. For all these reasons Australia was an attractive investment for the British Empire. Such a lucrative arrangement continued:
Newcastle, New South Wales was used as a penal settlement from 1804 to 1824 , convicts there worked as coalminers, cedar-cutters, and lime-burners. Port Macquarie ( 1821 – 30 ) and Moreton Bay ( 1824 – 39 ) also were used as penal settlements. Norfolk Island, re-settled in 1825,...held an average of 1500 to 2000 convicts, considered to be of the worst type. Punishment was harsh and a number of mutinies occurred. The last convicts left Norfolk Island in 1856. Port Arthur, in Van Diemen's Land (modern Tasmania), begun in 1830, was finally closed in 1877.
Note that the Dutch had established a port at Cape Town 150 years earlier, later used to receive prisoners. The French also attempted to establish presence, but more for trade reasons.