I'm from Palau, not quite all the way out to Australia and NZ, but say half way there. My memory is hazy, but I remember learning from social studies in grade school that when Europeans made first contact, they observed terraces that apparently for rice paddies which the Palauans didn't make (I think they could do that sort of thing to an extent but not quite a out of a complete hill side). When the European captain asked the natives whether they made the terraces, the Palauans said, "the gods made them." And I think the captain guessed in his logs that previous settlers (Chinese) had made them long ago and left them. So, even back then, Europeans knew explorers from other groups probably went before them.

This is a side tangent: I remember learning as a kid that legends had it that "gods" came out from the sea and taught the first Palauans skills and craft, like how to cook and fish, make canoes, build houses and all those sorts of things. That mixed with the above always lead me to believe those "gods" were just visitors from other islands or lands. Also, realize the island was no more than 60 miles from northern most point to southern most point, but my ancestors believed the universe ended a couple of miles beyond those tips on either end, so they didn't really conceive of other places or people. Our language does share strikingly similarities with some Indonesian words, and I've seen pictures of their ancient architecture which look eerily like some of ours. I'm not sure what makes more sense though, explorers randomly marooning and imparting knowledge and skills while integrating, or that the first settlers who would become my ancestors just bringing their culture and craft with them. The latter makes much more sense I guess from a logical perspective.