Job-hunters are being targeted in a scam where prospective employees are asked to cash cheques before sending money to Nigeria.
Customs officials have put out the warning after 364 counterfeit bank cheques - with a face value of around $2.5 million - were intercepted.
Customs investigations manager Shane Panettiere said the cheques looked suspicious as they were sent to one recipient.
The scam involved an overseas agent, thought to be from Nigeria, who set up several fake job listings on well-known websites including Seek, Trade Me and Gumtree.
Those who applied for a particular job were then asked to send details of their bank account, passport and driver's licence.
"You just whacked in a CV and applied for [a job] and then you got a response.
In this case, some of the recipients were told they've got the job, but they would like them to undertake some administrative-type tasks.
"One of these tasks will be that you'll get a cheque soon and we want you to go and bank it, keep some of the proceeds and send the rest overseas."
Mr Panettiere said up to 13 people in New Zealand came close to being sucked in.
"Fortunately, the scam was discovered at an early stage and no financial victims have been identified."
However, he said it was not known whether any counterfeit cheques had slipped through earlier and whether any had been cashed.
Jon Duffy, head of trust and safety at Trade Me, said they were made aware of a potential scam on the site in mid-June.
Five accounts were found to have been created by a scammer, three of which were not active, Mr Duffysaid.
The other two accounts had a job listing for a receptionist or administration assistant based in Auckland City, while the other account offered a job for a forklift driver. Ninety-two people applied for the positions.
The accounts had a Western name attached, and an Auckland address.
Both advertisements did, however, have grammatical errors, often a sign something is amiss.
Mr Duffy advised anyone who might have suspicions about a scam on the website to stop all communication and contact Trade Me immediately.