The Motor Trade Association is warning consumers to be diligent and cautious when purchasing cars from private sellers.
The MTA said roadside sales of vehicles spikes over the summer.
Its chief executive Warwick Quinn said people needed to know who they were buying from, and do due diligence and check out the vehicle well.
"Know who you're buying [from], know what the car is. Have it checked out because it might look cheap but in the long run in might cost you a bit."
Mr Quinn said it was worth paying for a pre-sale vehicle inspection.
Consumer NZ's website states that if you buy a car privately rather than from a dealer the Consumer Guarantees Act and Fair Trading Act do not apply. Its website states that if a private seller misleads you about the car, you can take them to a Disputes Tribunal.