Renting a car on Great Barrier Island is a bit different than mainland New Zealand. Fuel is more expensive and fuel stations are not open every day.  Most of the roads are unsealed, winding and narrow.  Take your time and enjoy the adventure.  If you pre-book your car will be waiting for you at the airfield or the wharf.  All rentals include complimentary transfers with Great Barrier Buses and you can use their services if you have any problems with the car such as breakdown or punctures.