The cost of a warrant of fitness could be forced up as mechanics spooked by a clampdown move to get out of doing inspections.
The Motor Trade Association (MTA) warns this could happen, especially if coupled with a push - which it is backing - to change what the outdated warrants system covers to include high-tech radar and suchlike.
"We've heard from inspectors who'll continue as mechanics or repairers but stop being inspectors because of the added compliance that may come," MTA chief executive Craig Pomare said.
"What the [Transport] Agency have said is 'we're going to reshape who gets to be an inspector, reshape the training and professional development required, then reshape the auditing and testing of them'.
"So I think, quite naturally out of that, we may lose a large number of inspectors because they don't meet the higher standards and I think that's a positive thing for the industry."
The Transport Agency (NZTA) has been ramping up its inspections regime after admitting in October to years of failing to enforce road safety rules.
A damning investigation released yesterday showed that not only did agency's front-line inspectors lack the power to suspend garages, senior managers had little idea how to do it.
William Ball, 65, died from injuries in a crash in which his seatbelt failed, less than a month after a Dargaville garage had issued a warrant to the car.
Uncertainty by a panel of senior managers over who could suspend the garage contributed to eight months of delays in doing so.
The report also showed the only people at the agency who actually did have that suspension power - a four-person adjudication team - were too busy to look at the Dargaville case as they spent 90 per cent of their time on commercial work, not car warrants.
The agency's frontline staff, the investigation found, had "no meaningful way" to take urgent action even when public safety was at stake.
NZTA board chairman Michael Stiassny said none of the failings discussed in the report were news to him.
"Unfortunately, no," he told RNZ. "There's nothing here that surprises.
"This is just a confirmation, sadly, of a position that we put forward as we found it late last year."
That discovery - which he made when he took the board chairperson job last April - came late.
The failings had been well-known for years by the MTA and others in the industry, who say they raised the alarm with the agency.
"Unfortunately, in many instances that hasn't gone anywhere," Mr Pomare said.
"The concerns that we as an industry had about rogue operators, about poor processes, about the inability of frontline inspectors ... to be able to get stuck in and deal with those rogues, that's all now ... fortunately, risen to the surface and is being dealt with, so we're delighted."
The failures were papered over officially, such as by a 2018 Performance Improvement Framework review that said the agency was "well-placed" in regulating the road; and the failures were made worse by a 2014 strategy that treated garages primarily as customers to be serviced but not policed, yesterday's investigation said.
Holding garages to account can't come soon enough for the MTA.
"Unlike in the past where they were given five yellow cards, if you will, in a row, they will be given one yellow card, given time to fix it. If they haven't [fixed it] a red card will be issued.
"So it's a fundamental change which we support - if there are rogues in the industry they need to be dealt with," Mr Pomare said.
AA Motoring Services general manager Stella Stocks said the change would be good as long as there was a fair process for garages to appeal.
"If we can give the people who are monitoring the providers more power to make good decisions quickly, then that's gotta be better for vehicle safety," Mrs Stocks said.
However, a trainer of mechanics, Brent Greenlees of Auckland, said a fundamental failing had not been reported on, and must be looked at.
"Training for warrant of fitness inspection, and Certificate of Fitness inspection, once you become a vehicle inspector is not compulsory, it's all voluntary."
He saw WOF inspectors who had not kept pace with rapid changes in technology that governed car safety systems "time and time again".
"It's not safe," Mr Greenlees said.
Mr Pomare said the MTA was talking to the NZTA about training mechanics, and updating the WOF checks themselves.
Among the fixes Mr Stiassny was shepherding through was a law change so the agency could force people to get their warrants redone.
At the moment it has only been able to advise almost 30,000 motorists affected by the suspension of more than a dozen garages that they need to get their warrant redone urgently.
They had already partially tightened up the quality management system that inspectors worked under and would keep working on that and tightening up other regulations throughout 2019, Mr Stiassny said.
The investigation report did not address who is accountable at the agency for the failings. Mr Stiassny said they would get to that in due course.
Already, the chief executive and three board members have resigned.