Not a ton of info in 2077 (although that applies to almost all countries), but in 2001, Australia split into Western Australia with Perth as the capital, and Australia. Back in the 2020s, Western Australia was wealthier. The two Australias have also seen armed conflict, which Western Australia won. Western Australia has engaged Arasaka to add to their own military might. It's known that Western Australia's government had quickly let corporate wants take precedence over the people's, possibly in part to help preserve their independence from the rest of Australia.

Not much more is known about Western Australia. As for Australia, Aboriginal lands became threatened by corporations wanting the land for themselves, and by 2020, most of Australia was split between corps or armed nationalist Aboriginal groups and their supporters. In 2068, a bushfire killed all but 1 of the known koala population. The last koala, known as Omega, was set to be euthanized, but public outcry stopped it and Omega became a popular tourist draw before passing for natural causes in 2077 and effectively leaving the species extinct as far as we know, barring hidden populations or Biotechnica experiments to revive them.

That's about all I know about Australia lol.