Although some quarters are suggesting Australia arm itself heavily in area denial capabilities, to "rip the arm off" a potential aggressor in the South West Pacific, I think this is more a firm and reliable commitment to the US alliance.
Australia did not feature in War Plan Orange. Though once the US bloodied, in the opening months of WW2, Australia became important strategically in the Battle of the Pacific. The Japanese addressed this, although did not have the capabilities to interdict US operations over the vast distances required. US submarine operations for instance, based out of Fremantle WA, operated into the no-less significant today ( to the Chinese if the Malacca blockaded ) maritime choke points of Sunda/Lombok/Bali straits. With advancing technologies and the vulnerabilities of US bases further north, Australia is slowly featuring heavily in US planning. Stockpiling of munitions and fuel is a clear indicator. No different to WW2 except that this time around, Australia should be far better equipped for the types of conflicts envisaged. With a Fifth Generation air force and a naval build up underway ( though oddly lagging sub-surface ) the Australian military is being well positioned to integrate with the US in countering China militarily. As well as adding to the efforts of deeper developing alliances with regional countries at varying levels.