air nz now has some affiliated schools that might be worth getting in touch with. i would be surprised if there arent a few instructors about sitting on yes letters atm. get hold of one of those blokes.
far as i knew the tech exam has revolved around a good working knowledge of the nz aip. jepp sections in particular atc, met, terminal etc. i'm a bit out of date now.
good luck with it.
kiwis dont seem to bother with pprune much.