Regarding registration our research indicates that due to exemptions this isn't required yards etc, or to cross a road:

Exemptions from registration and licensing:
In some limited situations, you may use an unregistered vehicle on a road. An unregistered vehicle can’t be licensed, which means in the two situations that follow, your vehicle doesn’t have to be registered or licensed.
Using an unregistered vehicle on a private road Your vehicle doesn’t have to be registered if you only ever use it on a private road. Private road means a road, place or arcade (eg a covered passage
giving access to a number of shops) laid out or formed on private land by the owner of that land.

Using a vehicle to cross the road
You can also drive an unlicensed vehicle on the road only to cross
the road.
Crossing the road doesn’t mean you can drive down the road for
any distance. You must be crossing in a direct line from one side
of the road to the other.

See https://www.nzta.govt.nz/assets/resources/factsheets/27/docs/27-exempt.pdf