Senior members of the Waikato Comancheros, the Waikato Mongrel Mob and the Head Hunters have been arrested as part of the New Zealand end of a massive international crime sting.

In a new conference this morning, National Organised Crime Group director detective superintendent Greg Williams said about 4pm yesterday, police conducted 37 search warrants across the North Island. Operation Trojan Shield involved more than 300 personnel.

Thirty-five people were arrested, with 900 charges laid, and $3.7 million in assets have been seized.

The arrested people have appeared in Auckland District Court and Hamilton District Court this morning on serious drug dealing and money laundering charges.

Police have also seized 20 ounces of methamphetamine, large bags of cannabis, mulitple kilograms of iodine, four firearms, 14 vehicles including two marine vessels, a number of mobile phones, and about more than $1m in cash.

Police were cautious to say if there would be a dent in the meth market as a result of the operation, Williams said. However, it had taken out some of those in the "top echelon" of organised crime.

More warrants were being conducted today and police expected more arrests.

Police have been running multiple operations - under the umbrella Operation Spyglass - as part of an international effort with law enforcement agencies to investigate sale and supply of methamphetamine and money laundering activities.

Operation Trojan Shield

Operation Trojan Shield was led by the Federal Bureau of Investigation (FBI) and co-ordinated with the DEA, Australian Federal Police (AFP), Europol and other law enforcment agencies from more than a dozen countries.

Photo: Supplied / NZ Police

Police said organised crime groups were using encrypted platforms to conducted international communications.

"It creates a massive challenge for us," Williams said.

As part of that, Canadian-based encryption service company Phantom Secure was dismantled by the FBI in 2018. Another service, Sky Global, was dismantled in March 2021.

NZ Police contacted the FBI in 2020 about a potential import into the country - the same year New Zealand became involved in this operation.

A special encryption platform was set up - ANOM - to access encrypted organised crime communications. Police said users unknowingly communicated on the system, operated by the FBI, for over 18 months.

The network had 57 devices in New Zealand using it and all were being used for criminal activities, Williams said.

It allowed access into several organised crime syndicates, Williams said. It also resulted in the Operations Equinox and Seltos being started.

Photo: Supplied / NZ Police

Police said they also observed significant money laundering by the groups involved.

"It's a key focus for us to disrupt those cash flows.

"We couldn't do this without our partners," Williams said. That included, for example, Customs.

"What we are actually talking about here is these transnational groups preying on our vulnerable communities."

Customs' Dana McDonald said customs was working with police on "insider threat".

"We don't have any intelligence that's indicated that's happened in this case."

He had no evidence of corrupt port staff assisting with criminal supply chains in current investigations.

Williams said since 2016 waste water testing showed there had been a bit of drop in meth use.

National Organised Crime Group director detective superintendent Greg Williams. Photo: RNZ / Dan Cook

Operation Van

It all started with Operation Van in 2018, which targeted a transnational organised crime group linked to the Comancheros, police said.

It was conducted with help from partner agencies and international ones, including the FBI and AFP.

Police allege the group planned to import huge quantities of methamphetamine and cocaine into New Zealand, but it never made it here. They also allege the group had used money laundering networks to move money offshore.

Operation Van resulted in the seizure of 137.5kg of methamphetamine from a storage unit in Rotorua in 2019.

One person plead guilty and had been sentenced for possession for supply, police said.

Operation Equinox

In another operation, Equinox, police seized 8.6kg of methamphetamine and 20 ounces of methamphetamine at the border.

Police allege Waikato Comancheros and Mongrel Mob Kingdom members worked with "offshore entities" to import large quantities of methamphetamine and MDMA for distribution acorss New Zealand.

Operation Seltos

Police also allege Auckland-based Head Hunters had dealt large amounts of methamphetamine in Operation Seltos.