Spain did very little around Australia, it'd take a big PoD to get them to set up a colony before the British. Besides, the Spanish settled the Americas very early, but those parts are the least industrialised, especially compared to the ex-Brit colony of the USA.
The Portuguese are supposed to have done some quiet exploration in the 1500s, but the Dutch did a lot in the early 1600s, so they're your best bet for pre-British settlement. The eastern half of North America's development is probably a good analogue as to what Australia would be like with an extra 150 years of European settlement.