Police have raided a number of locations across Auckland as they investigate a senior member of the Head Hunters gang.
This follows 'Operation Coin', an extensive investigation into the alleged accumulation of criminally derived wealth, police said.
Police on Monday carried out search warrants at various locations in Auckland, with the support of a number of other government agencies, including the Serious Fraud Office, Customs, Ministry of Social Development and Inland Revenue.
The Commissioner of Police was last week granted restraining orders from the High Court in relation to various properties that are controlled by the Head Hunters member, a 62-year-old beneficiary.
The value of the restrained property is approximately $6 million.
Police Financial Crime Group head Detective Superintendent Iain Chapman said a "significant amount of work" had gone into the operation.
"Police are committed to ensuring that people can not accrue wealth and assets as a result of criminal behaviour, at the expense of the safety of our community."
The investigation is ongoing.