Three Auckland men in their early twenties have been arrested for allegedly scamming Trade Me car sellers.
They have been charged with multiple counts of obtains by deception.
Waitakere Police hoped releasing information about the scam would help prevent other online sellers becoming victims.
Police said the accused men contacted sellers of high-end performance vehicles to arrange a test drive.
The alleged scammers then showed the seller a fraudulent bank transfer slip and convinced them the money would clear in their accounts the next day.
After driving away with the car the men then listed the it for sale through various Facebook pages using fake names, according to Police.
Constable Michael Reinecke of Waitakere's Tactical Crime Unit said the cars were often on sold to new buyers before the victim had realised they had been scammed.
"This can complicate matters because if the vehicle has been sold on before the seller has reported it stolen, and the end buyer has bought the vehicle and its title in good faith, they are the new legal owners and it is the original seller who ends up out of pocket."
In a joint investigation with Trade Me, Police found all the vehicles taken through deception that had been reported to them.
Similar scams targeting cellphone, laptop and jewellery sellers have also been uncovered.
Police warned online sellers to be vigilant when trading with strangers.
"Check their money is cleared in your bank account before handing over the keys. Don't get pressured into handing over anything you're selling until you're sure you've received the funds for it. A genuine buyer will usually be happy to wait for you to check," Reinecke said.