But the chief executive of VTNZ, Mike Walsh, said tougher tests for motorists were likely if tests became less frequent.
"In my view if they going to yearly warrants as proposed, and I don't necessarily support that, you need to see what standards have been set. Unfortunately, with the current system people rely on a warrant of fitness [WoF] as a safety check. Most people will buy tyres to get a warrant - people aren't used to buying tyres because they look below the minimum standard concerned, so the WoF helps with that."
He said his concern was around any compromise to road safety. Crash statistics were coming down and the WoF was part of that solution.
"Safety comes at a cost and what Gerry Brownlee is saying is it has to be reasonable cost, and I understand that. But I think there needs to be some close understanding and measurement to make sure any changes ... don't have [any] safety compromise."
Mr Walsh said the average failure rate for vehicles was about 30 per cent - and he believed the VTNZ failure rate was less than garages.
Most cars failed because of problems with tyres, lights, brakes, suspension or windscreens, all hugely important for safe driving.
He accepted other countries already had yearly WoF testing but felt those situations were not directly comparable with New Zealand's.
"Our [average] vehicle age is 13 years and is getting older. We don't all travel in the same direction on nice flat roads."
Tougher standards - and therefore tougher testing - was likely.
"I would expect if they go to more than six months there would have to be some recognition that they need to have some tougher safety standards, otherwise you have safety compromised on the roads."
Insurance Council chief executive Chris Ryan thought annual tests for modern cars was adequate. "Cars are lasting a lot longer."
AA motoring affairs spokesman Mike Noon told Newstalk ZB road safety had to be the main thing.
FIT FOR ROAD
* Car owners spend about $250 million a year in inspection fees.
* There are 5.5 million warrant of fitness inspections a year.
* Thirty per cent of cars fail the first inspection at VTNZ outlets at six-monthly tests.
* Officials will now speak with key stakeholders; public consultation will begin in June.
* Decisions on proposed changes expected by end of the year.