Why on earth is that the case ? I had a quick look the regs in both countries are completely different.seems you cannot just walk in and swap licenses etc.
Why not just let anyone from anywhere cat1 just fly in either place ?? Looks like they try to follow Europe sharing things but botched it up ...still need passport etc pilot and mechanics not recognized .
Check out this
http://www.dfat.gov.au/geo/new_zealand/sam.pdf it explains the single aviation market between Austrlalia & New Zealand. Also see
http://www.icao.int/sustainability/C...-Tasman_En.pdf