As an Australian with an OZ ATPL, I have held a NZ ATPL since 1988 and kept it current each six months via a medical and paperwork showing hours flown. About 7 years ago when it was obvious I was never going to use the NZ ATPL I decided not to renew the NZ medicals although I kept my Australian ATPL current via normal procedures, medicals etc.
Then the possibility of a job in NZ was on the horizon so I applied via the TTRMA for a NZ ATPL as I was fully current including CIR on the Australian ATPL.
The NZ CAA knocked me back saying as I already held a NZ ATPL I couldn't have a second ATPL via TTRMA - but as my NZ ATPL was invalid after 5 years of no renewals I couldn't use that either. Catch 22. However, the NZ CAA said, if I want my NZ ATPL back all I had to do was ATPL Air Law, undergo a NZ instrument rating test, do a medical and I think a ATPL flight proficiency check. Very expensive plus air fares to and from NZ.
I said thanks for all that, but how about I send my NZ ATPL back in the post to you and you can delete it from your licence register and then give me another new NZ ATPL via the TTRMA? Sounded a reasonable idea to me. No can do said the NZ CAA as that would be against the spirit of the TTRMA.
The job disappeared over the horizon of course. Bureaucracy won hands down.