Russia Ukraine war, page-208357

instead we sent our troops to Vietnam, Iraq and Afghanistan for the Americans after they took the reins from the Brits who went broke running an empire. I don't think Germany or Japan would have actually invaded Australia - its a difficult place to invade and we were much more self sufficient in ww2 making artillery shells, bullets, bombs, and grenades, fighters, bombers, and reconnaissance planes, warships, including destroyers, corvettes, and other naval vessels, uniforms, rifles, machine guns, boots, helmets, and field gear.

The one thing we lacked was fuel (and still do!)

we were early pioneers in Shale and also synthetic fuel from coal
https://en.wikipedia.org/wiki/Oil_shale_in_Australia