The police have seized nearly $8 million in cryptocurrency and other funds following an investigation by their Waikato/Bay of Plenty Asset Recovery Unit.
They say the US Inland Revenue Service alerted them in 2016 to a website operated by a man based in New Zealand.
It was allegedly distributing a large number of copyrighted films and laundering the proceeds.
The man and his associates were reportedly using online money transfer services to send remittances between the US, Canada, New Zealand and Vietnam.
The police say their investigation resulted in the restraint this year of $6.2m in cryptocurrency and $800,000 in banked funds from the man allegedly involved.
This month a further $472,000 in cryptocurrency and $377,000 in banked funds were seized from an associate.
Assistant Commissioner Investigations, Serious and Organised Crime Richard Chambers said New Zealand police work closely with international law enforcement agencies to prevent money laundering and the partnerships had proved valuable for the current case.
He said cyber-crime and money laundering often cut across international boundaries.
Detective Senior Sergeant Keith Kay of the Asset Recovery Unit said: "Introducing illicitly-obtained funds into New Zealand constitutes money laundering and police will thoroughly investigate and restrain the assets of those who undertake such activity."