The average age for a vehicle without insurance was 1995, three years older than New Zealand's median vehicle age.
The average odometer reading was also higher for uninsured vehicles at around 205,000 km travelled in comparison to 154,000 km as the national average.
Results also showed that 51 per cent of participants without any insurance on the vehicle they were driving earned less than $25,000 a year.
MTA spokeswoman Ana Zandi said the results were surprising but showed skimping on basic vehicle requirements is a reflection of tough economic times.
"Our results show that people are not only cutting back on basic vehicle costs such as insurance cover, but some are also failing to relicense ('register') their vehicles, with an estimated 50 per cent holding off servicing their vehicles.
"Clearly a person's income level directly affects their ability to insure their vehicle or carry out routine vehicle maintenance along with keeping up with vehicle relicensing ('registration') requirements. This is not an ideal scenario. Longer term, owners risk the safety of their vehicle as well as other road users. Interestingly, they are also reducing their vehicle's ability to maximise its fuel efficiency."
Regions with high levels of motorists without insurance included Wellington (21 per cent), Manawatu (20 per cent) and Auckland (19 per cent). Only 10 per cent of Christchurch motorists surveyed had no insurance.