The Transport Agency has banned another vehicle inspection business over its poor Warrant of Fitness assessments.
Westland Automotive and Tyre in Auckland was suspended and its director Akram Zakeri stood down as a vehicle inspector, for failing to check brakes, seatbelts, steering and exhaust systems.
Last week the agency admitted they knew for years that a mechanic in Dargaville was not doing proper checks, and only clamped down after a fatal car crash.
Transport minister Phil Twyford said it is unknown how many other mechanics could be suspended.
Law firm Meredith Connell is currently working through 850 files of mechanics which were found to not be properly processed, 157 of which were "coded red" and needed urgent action.
He said 19 of the firms are currently under investigation.
"There well may be other cases that will emerge."
Mr Twyford said NZTA is alerting everyone who's had a warrant issued by the Westland mechanic and will provide a voucher for a new warrant of fitness.
"There will be a hefty bill," he said.
"There are 19 vehicle certifiers that are currently still being investigated" - Transport minister Phil Twyford
An external inquiry into the NZTA is underway.
Previous Transport Minister Simon Bridges said none of the matters had ever been raised with him.
"These were matters the associate transport minister had," Mr Bridges said.
Mr Twyford said there had been a "systemic failure" across "one of our most important agencies."
"It's been going on for a decade. It cuts right across the regulatory work of the transport agency and we're going to put it right.
"It's extremely disappointing and we are dealing with it as fast as we can," he said.
"When all this is done, I'm not going to rule out the fact that heads may roll as a result of this organisational failure.