Currently, in New Zealand, there is car-sharing, car rentals and taxis, all offering EVs.
The following links may help you:
Easy Transport Waiheke
My Car Your Rental
Car Sharing: Because owning a car is no longer the future. Millions of people around the world are already very successfully car sharing. Remove the pains & costs of owning your own. Yoogo Share is a membership-based service and is free to join. They have bases in Christchurch and now Auckland. Vehicles available are BMW i3 and Hyundai ioniq.
EV Rentals: If you need a longer rental, try Europcars, available at Auckland, Wellington and Christchurch Airports. Vehicle type available is Volkswagen eGolf. My Car Your Rental has several privately owned electric vehicles on it's books, available for renting per day.
EV Taxis: On Waiheke Island, an all-electric service is available at Easy Transport. Offering Nissan LEAF and eNV200 van. We understand that Green Cabs is no longer operating.