Thieves are targeting custom-made car transporters and are thought to be using the vehicles to hide stolen cars.
Constable Aimee Brinsley said it was the first time she'd encountered the specialised trailer theft in eight years working with the burglary squad.
On Tuesday, Januray 21, thieves made off with two distinctive car transporters from a caryard on Hillside Road, Wairau Valley, North Shore.
The thieves ignored caravans and other vehicles nearby, making a beeline for the big trailers.
Two distinctive car transporters were stolen from "U Sell" Car Yard between 2.30am and 8am.