I know of two pilots who had Oz ATPL issued on the basis of PNG SCPL/ATPL issued on basis of US ATP and one was told by
VB to go and get Oz subjects...when he subsequently failed one subject his Oz ATPL was rescinded. When he had passed them all
VB had 'lost interest'. The other withdrew his application with
VB as a result.
Whether the same applies to an Oz ATPL based on a US ATP that has actually been used within the US I don't know. Certainly though the Oz 'majors' don't like people who have clearly used the system to take the lazy/easy way out and avoid the Oz exams.