I,m not sure I fully understand why you need to have a type that you are rated on in EASA land to do your conversion in NZ.
The long and the short of it are you will need to be rated on the machine that you need to use for your test regardless of where the rating was issued.
Anyway there are S76s in EASA and there are S76s in NZ that are operated IFR and are used for ATPL flight tests.
It may be worth calling NEST (Northland Emergency Services Trust) and asking about what you want to do.
They also have a certified sim up there for IFR training as well.