Police are warning anyone caught issuing fake warrant of fitness stickers could face criminal charges.
Cars have been turning up at a Northland service station with warrants issued by a Māori sovereignty movement. Rawene Service Station owner Mandy Hauraki told RNZ the fake warrants were a joke - but also a scam.
The stickers state they have been issued under the "Native Waka District Motor Vehicle Act 2005".
But police said the warrants are not legal, and drivers who had purchased them should not use their cars until they have a legal warrant of fitness.
AA's general manager for motoring services Stella Stock said the fake warrants were worrying because it could mean unsafe cars were on the roads.
"Make sure that you go to an outlet that is authorised by the Transport Agency to have your warrent of fitness completed.
"And make sure the sticker that's issued for it is the correct sticker, [and] you will be able to find out what that looks like on the NZTA website."
The Transport Agency said drivers who are not displaying an approved warrant will be fined, and anyone worried they may have a false sticker should get in touch.