If you are buying from a private party, take these steps:

Check the Private Property Securities Register (PPSR) to see if the car is listed as security for a debt by the current owner.

Check with an LTNZ agent (see list below) if the car has been reported stolen.

Both the buyer and the seller must report the sale. Official change of ownership can be file online at Land Transport NZ's transaction site.

Or you can file a paper form in person at a LTNZ agent:

NZ Post

Automobile Association - AA

Vehicle Testing New Zealand

Vehicle Information New Zealand

On Road New Zealand

With either option, the change must be submitted within seven days of the purchase.

Note that the Consumer Guarantees Act does not apply to used cars purchased from private parties. So it is best to have the car examined by a qualified mechanic before buying.

General information can also be found at:

Land Transport NZ

Ministry of Consumer Affairs