A Hamilton vehicle inspector who allowed unauthorised people to inspect vehicles and issue warrants of fitness has been immediately suspended by the Transport Agency.
The owner of Frankton WOF and Tyre Station Sayad Hussein has also failed to correctly inspect some vehicle lighting, braking and exhaust systems.
The NZ Transport Agency (NZTA) said it is unaware of specific concerns relating to individual vehicles.
However, due to the poor quality of Mr Hussein's inspections it is possible some vehicles may have been incorrectly passed, NZTA said.
It strongly encourages people who have a current warrant of fitness issued by Mr Hussein to get their vehicle rechecked.
NZTA will contact all 2836 affected vehicle owners as soon as possible and give them a voucher to get their vehicles rechecked.
More than a dozen inspectors or garages that issue warrants have now been suspended as part of a nationwide investigation, affecting 20,000 cars.