Maybe this is why plates are expensive.... I did not know about the security feature before...
Security Feature
All plates are made containing a silver fern security feature in the sheeting. The silver fern is created during the
manufacture of the reflective sheeting. This unique image is for New Zealand (other countries have their own
image). The image can be seen if you turn the plate to a 15–30 degree angle. This feature is to assist the
identification of an authentic plate from a fake.
Only plates issued by Waka Kotahi NZ Transport Agency and its agents are legal. Plates purchased anywhere else
are unacceptable.
Number plates | Waka Kotahi NZ Transport Agency (nzta.govt.nz)