"But the problem is most vehicles have a built-in life expectancy. It comes a point where the maintenance and servicing costs will actually start to rise to the point where it becomes uneconomical to keep the vehicle."
Mr Van de Steeg said the worst case he had ever dealt with was 10 to 15 years ago when a car was so bad, he would not let the owner take it out of the workshop.
"I had to call the police and say 'I'm not letting this car go' and give the keys to them. I remember one where we were putting the vehicle on the hoist and the front of the car basically almost fell off - that was an extreme case."
MTA spokesman Ian Stronach said the national fleet age was old compared to other benchmark countries. As a consequence, New Zealand's fleet lacked standard modern safety features such as airbags and ABS braking, he said.
The comments follow the Government's announcement of a shake-up of the vehicle licensing system, which included a proposal to extend the current six-monthly Warrant of Fitness tests on cars more than six years old to 12 months.
