Oh at last something on MN that I know something about.
First off - we have diesel!!
Second - yes you need to have owned it for 12 months prior or will be stung for huge import taxes.
Then - cars imported into NZ have to be in truely excellent condition - we imported a 1980's classic which was in top notch excellent condition for its age in the UK and which was taken apart and stripped down to its sills and needed respaying etc etc at ENORMOUS cost. So unless your car is really quite new, like within the warranty period, or is a classic that you can't bear to part with, take great care.
Then - it will need various certificates and registrations when it gets here - more expense.
Finally - cleaning - with a toothbrush. EVERYTHING needs to be pristine and spotless. The car will be in a container and crossing the tropics for weeks - the slightest bit of dirt will attract bugs and mould and mildew.
This last part - cleaning - if you are moving to NZ clean everything with a good smelly disinfectant or buy the stuff that they say to use online - I imported bikes, a kayak, boots, car, camping gear - everything is opened and inspected - and nothing got fumigated because it was all super clean. Put all the shoes in one box and make it clear what is there so that hopefully MAFF only take that box apart.