Trade Me is telling buyers to be wary of scammers posing as sellers in the lead up to Christmas.
The trading website said scammers have been texting phone numbers left by interested buyers, pretending to be the seller and asking for money.
Trade Me head of trust and safety John Duffy said the practice, known as text scamming, is mainly used in auctions for expensive electronics.
He said someone is currently under investigation by the police for text scamming.
Mr Duffy warned interested buyers not to put their mobile phone numbers on the site as it will expose them to scams.