An Invercargill garage is in trouble over warrants of fitness affecting more than 3500 vehicle owners.
The Transport Agency has revoked the inspecting authority of mechanic Donald McLean, and of his garage The WOF Man Limited.
"Mr McLean has a history of compliance issues and upheld customer complaints relating to the poor quality of his inspections," the agency said in a statement.
He failed to properly inspect brakes, exhaust systems and corrosion repairs, and let his personal issuing authority to be used for WOF inspections he did not perform.
"We are unaware of specific concerns relating to individual vehicles however, due to the poor quality of Mr McLean inspections, there is a possibility that some vehicles may have been incorrectly passed."
It would be contacting 3515 vehicle owners to advise them about the options for a re-check, and provide vouchers for that, the agency said.
Another four inspectors or garages around the country have had their ability to issue warrants revoked, and 20 have been suspended.