Unless you are likely to need a NZ licence, I can't see any advantage in trying to short cut the system by getting that first then converting to a CASA ticket under the TTMRA.
You would be up for two initial ATPL medicals (with all the attendant other tests), simulator preparation plus one flight test in NZ, and the possibility that you'd still need to do a CASA IPC to be employable, so add more preparation anyway - unless you could find an Aussie operator willing to do that for you as part of their induction process (good luck with that!).
Regarding the comment above about a licence that is the conversion of another licence being acceptable to CASA , be very careful ! It may be the case, but there was also a time when CASA clamped down on Aussies who were too thick to pass the ATPL exams here skiving off to the USA, feeding money into a vending machine in Fort Worth Texas, waiting for the ink to dry, and returning a week later with a FAA ATP to convert. CASA quickly woke up and so it became policy when assessing applications to ask for proof that the pilot had actually done some operational flying in the USA. This was probably a good call, given that at least one of the USA training outfits at the time advertised "Examiners on staff - pass guaranteed". Standards in the USA have improved somewhat since then, and I'd venture that their handling test is more demanding than ours. Our mob are more obsessive about pissant rules, so it is these that you will need to get your head around.
If the licence you are using to convert contains a statement such as "issued in recognition of ATPL number ... issued by........" you could come unstuck. My experience with CASA is that they want a letter from the other authority that the licence was an initial/original issue. I could be wrong, but it's worth double checking. I have only used the TTMRA to go from CASA to CAANZ, and it was painless (took me 5 days), but I have heard a few horror stories about pilots coming the other way.
Add travel, accommodation etc and waiting time for the authorities-who-must-be-appeased to assess your application. Six weeks in NZ, six months in Oz.
Last edited by Mach E Avelli; 8th Jan 2024 at 03:34.