New Zealanders being rung from overseas are being duped into allowing access to their computers and bank accounts.
The scammer cold-calls the victim, claiming to be from an IT support help desk, plants malware in the computer through the phoneline and offers to fix it for a fee paid by credit card over the phone.
Christchurch mum Claire Kelly's computer was hacked by a man who rang up offering to fix something on it.
"They said it was quite a major problem, a new problem, and that a lot of anti-virus software people had on their computers was not detecting this virus," Kelly told ONE News.
But she said when she followed the virtual PC doctor's advice, things got weird.
"Windows just kept popping up and the mouse kept moving around and I had this absolute sick feeling in my stomach."
NetSafe believes the scammers are increasing the intensity of the scam, with six foreign calls reported in New Zealand yesterday. Australia has had a tenfold increase in the past two months.