"The victims in these cases have often lost tens of thousands of dollars, with one victim losing around a quarter of a million dollars to the scammers.
"In many of these cases, the victims are told to download software from a website which has then given the scammers access to the victim's computer, where they have unwittingly transferred funds out of the individual's bank accounts."
Since July, police have arrested 12 men and one woman, aged between 21 and 33, for money laundering and their cases are currently being heard in court.
Blackman said the arrests have taken place in Auckland, Hamilton and Napier.
"I want to reassure the community that police treat these scams seriously," he said.
"We know there are more offenders out there targeting victims and we will do everything we can to identify them and hold them to account."
Police are currently seeking the public's assistance to help find three men who have warrants to arrest for money laundering in relation to the investigation.
They are Manish Khan, 24, Tushar Prabhakar, 21, and Hitesh Sharma, 22.
"These three men are believed to be in the Auckland area and have links in particular to South and East Auckland," Blackman said.
"They are also known to frequent the Auckland Airport area and Auckland Central, including SkyCity.
"We want to hear immediately from anyone who has seen these individuals."
Blackman said police are concerned that despite public warnings, they are still continuing to receive reports of people falling victims to this scam.
"We really need the community to help us spread the message to their friends and family, particularly the more vulnerable, elderly members of our community, to make sure they are also aware of this scam.
"The victims are always rung on their landlines at home. This is an important reminder to never give your personal details over the phone to a stranger."
A legitimate business or a member of the New Zealand Police would never ask for bank details over the phone or for the transfer of money, Blackman said.
"If you think a call may be suspicious, hang up immediately," he said.
"If you have concerns about a call, ring the company back on their publicly listed number, not the number they have called you on, and alert them to the call you have just received."
Police encourage anyone who may have lost money as a result of this alleged scam to report it to their local police station if they have not already done so.