Waikato Police warns users of on-line adult internet sites to be wary after several people, who had used such sites, became victims of extortion recently.

Hamilton CIB Detective Senior Sergeant Ross Patterson says detectives have so far dealt with two victims but suspect there may be several more who haven't come forward.

Waikato Police urges everyone who uses on-line adult internet sites to proceed with caution. To date they know of two people who have become victims of extortion but believe there may be more people who have not come forward. Photo: Thinkstock

'It appears overseas based fraudsters are preying on New Zealanders who engage in online sexual activity and once they have made contact with the person, cash is demanded.

'The demand for cash is accompanied by a threat that explicit footage of the victim engaged on the adult site will be uploaded on social media sites if money is not paid over.”

Ross says one of the main challenges for investigators is that extortion complaints are difficult to pursue as the offenders are largely based overseas.

So police are issuing a broad warning to users of internet based adult websites to be aware, he says.

'it appears users are being watched and they may become a victim of attempted extortion.”