Problems with brakes, tyres and lights were all regularly found during inspections, he said.
"If we see someone's tyres are getting down, we try and tell them but it will be a lot harder to do this if they only come in once a year."
A proposed "mileage system", where cars are checked after they have travelled a certain distance, could help counter the problem, he said.
The ministry proposals include streamlining the Warrant of Fitness scheme and changes to the vehicle registration programme.
Currently, vehicles must be inspected every six months if older than six years. Newer vehicles are inspected annually.
At a cost of about $50 per inspection, Kiwis are forking out nearly $250 million in fees each year.
Proposed changes include tougher testing standards, but less frequent inspections and the introduction of demerit points penalising those who don't comply with WoF safety standards.
A further seven changes to vehicle registration are included in the document, plus new options for the Certificate of Fitness and Transport Licensing.
The AA says the changes could bring New Zealand into line with the rest of the world.
"New Zealand is the only country in the world that requires most vehicles to undergo a safety inspection every six months," spokesman Mark Stockdale said.
"Most countries only require an inspection once a year or every two years, and in many Australian and US states, there is no regular inspection at all."
Associate Transport Minister Simon Bridges said about $245 million was paid in WoF inspection fees by Kiwis each year.
"And the time spent getting a WoF is estimated as worth $100 million.
"But, it is unclear whether this results in fewer crashes caused by vehicles."
HOW WE RATE
Average number of vehicle safety inspections over an eight-year period:
New Zealand: 13
NSW, Australia: 3
United Kingdom: 6
Germany: 3
Japan: 2
