Police in Auckland say more than 150 people have fallen victim to a scratch and win ticket scam.
They say the scam, run out of China, has netted the fraudsters up to $4 million since the middle of last year.
It involves people receiving travel brochures and scratch tickets in the mail.
They are then put in touch with the 'prize' sponsor and, once they have verified they are the winner, the victims are asked to pay upfront fees.
Detective Senior Sergeant Aaron Pascoe said in some cases police had identified victims and warned them yet they keep handing money over to the fraudsters.
"The general rule is if it seems too good to be true, it almost certainly is. And you never, ever pay money to release winnings. If you're asked to pay money to release winnings, it's guaranteed to be a scam."
Mr Pascoe said it was common for people to lose $20,000 to $30,000 at a time.