Whangarei police area prevention manager Senior Sergeant John Fagan said police had dealt with a number of people selling stolen property through Facebook pages.
"A word of warning about those Facebook pages where people offer goods for sale.
"It's (sometimes) the modern version of getting something cheap after it's fallen off a lorry or from a man down at the pub," Mr Fagan said.
"We also see plenty of people being ripped off with non-existent goods.
"Victims of dishonesty crimes are also finding their property on these buy, sell and swap pages, which has allowed us to follow up and retrieve their property."
"Our warning is that you have no comeback through Facebook if the trader or the goods aren't legit.
"You run the risk of attracting police attention if you are reckless and purchase goods that could possibly be stolen or cheaper than you'd expect or have missing serial numbers."