In the days before aerobridges ( 70s and early 80s) NAC/AirNZ did let passengers leave the 737-200 by the front and the rear door at Dunedin. Rear door was then closed and all boarding was through the front.
Ansett/TAA used to board passengers through the ventral stairs of 727s/DC-9s at non-aerobridge airports. Virgin Blue does use the rear door at Australian domestic terminals. Airports in NZ are not more dangerous than Australian airports, are they?