Originally Posted by
abmj-jr
Different carrier or not, is it all on one PNR (itinerary?)
If is a completely different itinerary then you should be ok. If it was all booked on one itin, even with different carriers, then you will have a problem.
That is the wrong question. The question is whether that onwards segment to Australia is on a separate ticket. PNR's, itineraries, and carriers are irrelevant.
OP has been asked the specific question twice and the answer to the separate ticket question may make a very significant difference.