Why are New Zealand and Papua New Guinea joined to Australia?

New Zealand and Papua New Guinea are not joined to Australia.
Papua New Guinea lies 150km to the north of Australia's northernmost point, while New Zealand is 1250km from the Australian mainland. Sometimes, the two nations are grouped in the general region known as Australasia.
New Zealand and Papua New Guinea are not joined to Australia.
Papua New Guinea lies 150km to the north of Australia's northernmost point, while New Zealand is 1250km from the Australian mainland. Sometimes, the two nations are grouped in the general region known as Australasia.