NZTA access and use manager David Pearks said they were hearing from a growing number of buyers who had found the condition of the vehicle they bought from auction websites was not as advertised.
"There seems to be an increasing number of people who see a car on the internet for sale, and think the photos displayed are sufficient enough to give an indication of the condition of a car," he said.
People needed to be more vigilant and carry out pre-purchase checks before buying a car online.
"We would urge all buyers of vehicles over the internet to carry out an on site pre-purchase inspection of the vehicle before committing to buying it, or to use services of an expert to do this on your behalf."
Trade Me commercial head Jimmy McGee agreed and encouraged the website's users to get as much information as they could before buying.
"Trade Me provides a car buyer's checklist at the bottom of each used car listing, encouraging every buyer to undertake a vehicle information report," Mr McGee said.
This would check whether money was owing, whether the odometer had been wound back, or if the car was stolen, he said.
Mr Pearks said a warrant of fitness was not always a perfect guide as a vehicle's condition could deteriorate considerably between WoFs.
