google up a flight school out of Ardmore , North Shore, Taupo.?? Sure to be an aircraft available someplace.
VERY spectacular country to have a look at but make sure you talk to a few folk who can brief you about mountain flying and the very variable islands weather.
Or better still get into the high country with a mountain pilot instructor to show you the ropes. Trust you appreciate "rivet testing" !!
Fly safe.