The Automobile Association has rubbished claims by some motoring experts that if proposed changes to Warrant of Fitness tests go through, there will be dozens of preventable deaths.
An expert panel, headed by Dog and Lemon Guide editor Clive Matthew-Wilson, said today that officials had deliberately underestimated the number of probable deaths and injuries that could result from the changes.
The panel said changes to the system from six-month checks to 12-months could cost more than 80 lives each year.
Transport officials said increasing the time between WOF (Warrant of Fitness) checks would cause only a few extra deaths per year, Mr Matthew-Wilson said.
"However, the Government appears to have deliberately ignored research that completely contradicts this view."
He pointed to a study from Germany that suggested 10 per cent of vehicle crashes were caused or strongly affected by defects in the vehicle. Monash University in Australia, suggested the figure was actually 24 per cent.
Australian vehicle accident expert Chris Coxon, who co-founded Australia's New Car Assessment Programme crash test program, said New Zealand Government scientists appeared to have deliberately excluded research that did not support the Government position.
"That's not science. No scientist should ever exclude data merely because it doesn't support his case."
Racing driver Greg Murphy said vehicle defects were far more important than many people realised.
"New Zealand has old cars and really rough roads. For about three quarters of Kiwis whose cars are over six-years-old, a WOF check twice a year is how they know their cars are safe."
However, the Automobile Association (AA) said people warning about increased road deaths were misleading the public.
AA spokesman Mark Stockdale said there was a big-budget campaign being run by commercial providers against the idea of any changes to the WOF system, and the AA was concerned the campaign was not presenting the full facts to the public.
"Some of the opponents of change to the WOF system seem to be cherry-picking information and not mentioning the time and cost benefits for motorists from a revised testing scheme, nor the changes we can make to improve vehicle safety."
"As part of the AA's analysis of the changes being proposed, we looked at the data on every fatal crash in New Zealand over five years from 2007 to 2011. The data showed that out of 1640 crashes, there were 89 (or 5.4 per cent) where a vehicle fault or factor was found that may have contributed to the crash."
Of the vehicles in those 89 crashes, 39 per cent did not have a current WOF and 52 per cent had a tyre fault.
Analysis of overall NZ road crashes indicated that vehicle faults contribute to about 2.5 per cent of all fatal and injury crashes and 0.4 per cent where the fault is the sole cause of the crash.
The most common factors contributing to fatal crashes were alcohol or drugs, and a driver losing control and going too fast for the conditions, Mr Stockdale said.