There is always more to say, but there was certainly contact, and I covered the trade between the people of Makassar (Sulawesi) and indigenous Australians from the "top end" of the continent in this earlier response, which links to a longer essay of mine on the same topic and to an AMA done with a flair whose specialism was Indonesian history.
Some additional details and further links can be found in an earlier thread that you can find here, which covers similar topics, and is led by u/Reedstilt