Your challenge, should you choose to accept it, is to have Australia divided between the colonial empires of at least 2 European states by 1850 with a POD after 1700. Bonus points if the POD is after the arrival of the First Fleet at Botany Bay and New Zealand is also divided.
2 shouldn't be too hard. Dutch West Australia is a possibility if the Dutch found a reason to settle it. I have seen a colony of shipwreck survivors used twice on this board. There could be other reasons, earlier discovery of gold or something like that.
France West Australia is certainly possible, as one of the reasons for the British to settle it, was because the French were planning to do it and the British wanted to avoid that.
Other countries are harder (unless you see an earlier united Germany that wants to setle it), only Portugal is close enough.
A third country is harder, but you could in theory see a northern Australia ending up for some reaon in either Dutch or Portuguese hands. But it will be a small colony, most likely part of their colonies in the Indonesian islands.