New Zealand Police say they have dealt a "huge blow" to organised crime after a major trans-national sting resulted in 35 arrests and $3.7 million in assets seized.

Police this morning gave new details about a large-scale international police operation that took place throughout New Zealand and overseas in recent days.

Operation Trojan Shield involved three major organised crime investigations and targeted the importation, sale and supply of methamphetamine, as well as money-laundering activities.

Over 300 staff - including National Organized Crime (NOCG), Armed Offenders Squad, Special Tactics Group, Asset Recovery, High Tech Crime and Auckland, Waikato, Bay of Plenty, Central and Wellington District staff - executed 37 warrants yesterday.

As of last night, 35 people had been arrested - they had appeared in the Auckland District Court and Hamilton District Court this morning facing a range of drug-dealing and money-laundering charges.

Senior members of the Comancheros in Waikato, Waikato Mongrel Mob and the Head Hunters were among those arrested.

Over 900 charges have been laid.

There were still outstanding arrests to be made, National Organised Crime Group director Detective Superintendent Greg Williams said.

One of the police operations - dubbed Operation Van - had specifically targeted the trans-national organised crime group linked to the Comancheros.

Williams said these groups had been "preying" on some of New Zealand's most vulnerable communities.

As part of the operation, up to 8.6kg of meth had been seized at the border.

Large bags of Cannibas were seized. (Photo / NZH)

Large bags of cannabis, multiple kilograms of iodine, four firearms, 14 vehicles and motorbikes, more than $1 million in cash and a number of mobile phones had also been seized.

In the past three years, NZ Police had found up to 20 organised crime groups that had been carrying out crime across international borders.

"This is a stunning piece of work," Williams said of the operation carried out by authorities both here and overseas.

"We believe the termination of these operations will have a significant impact on New Zealand's organised crime scene."

Offending across borders

It is understood those involved have allegedly offended across borders of multiple countries.

One of those who appeared at Hamilton Dictrict Court this morning is a 41-year-old Auckland man facing 68 charges, ranging from money laundering to importing methamphetamine and MDMA.

His other charges include conspiring to import MDMA and conspiring to import cocaine.

The offences are alleged to have been carried out, mainly in Hamilton or the Waikato, between 2019 and last month.

One charge relates to the alleged importation of 2kg of methamphetamine, on June 15, last year.

Many offences were alleged to have occurred with 11 co-accused, however most relate to one or two other co-accused.

He also faces charges of supplying methamphetamine and MDMA.

One charge, for which he is jointly charged, also relates to conspiring to import cocaine at Thailand on October 2 last year.

The money laundering charges relate to cash totalling more than $700,000.

Police last night confirmed they were executing a number of search warrants at properties in the Auckland, Waikato, Bay of Plenty, Central and Wellington districts.

Police outside a property in Pt England, Auckland, last night. (Photo / Hayden Woodward)

41-year-old man faces 68 charges

One of those who appeared at Hamilton District Court this morning is a 41-year-old Auckland man facing 68 charges, ranging from money laundering to importing methamphetamine and MDMA.

His other charges include conspiring to import MDMA and conspiring to import cocaine.

The offences are alleged to have been carried out, mainly in Hamilton or the Waikato, between 2019 and last month.

One charge relates to the alleged importation of 2kg of methamphetamine, on June 15, last year.

Many offences were alleged to have occurred with 11 co-accused, however most relate to one or two other co-accused.

He also faces charges of supplying methamphetamine and MDMA.

One charge, for which he is jointly charged, also relates to conspiring to import cocaine at Thailand on October 2 last year.

The money laundering charges relate to cash totalling more than $700,000.

Search warrants executed across NZ

Police last night confirmed they were executing a number of search warrants at properties in the Auckland, Waikato, Bay of Plenty, Central and Wellington districts.

One of the warrants was believed to have been executed in Pt England, Auckland, last night, when a resident saw armed police on the street.

Multiple kilograms of iodine, 20 ounces of methamphetamine and large bags of cannabis among the items seized. (Photo / NZH)

Later, a house was cordoned off and numerous police officers - some of whom were armed - could be seen outside.

A witness said a motorcyclist drove past the house at high speed, seemingly without noticing the police. The man then returned and parked his bike before going into the nearby dairy.

When he left he was spoken to by police and taken into custody.

In West Auckland, locals in New Lynn said they had seen police around Rua Rd and nearby Croydon Rd last night.

"Saw two unmarked police cars on Rua Road today - two cops with assault rifles stood at the end of the driveway by the crossing."

Residents in and around Whakatāne also reported seeing a heavy police presence in Ōpōtiki yesterday evening.

Staff at the News Whakatāne said they had received "multiple reports" of police there last night.

Criminal communications intercepted

Operation Trojan Shield, led by the FBI and co-ordinated with the DEA, AFP, Europol and other law enforcement partners from more than a dozen countries, is a covert law enforcement operation infiltrating encrypted devices used by trans-national crime groups.

In the past, the FBI has dismantled encrypted platforms criminals used to communicate.

Operation Trojan Shield saw the FBI create a closed encrypted company, called ANOM, to fill this void and to target organised crime, drug trafficking and money laundering activities across the globe.

For over 18 months, ANOM's criminal users unknowingly communicated on the system operated by FBI agents.

New Zealand Police began working with the FBI on Operation Trojan Shield in January 2020 to monitor the communication of platform users in New Zealand.

Information between the agencies led to the commencement of two local operations targeting drug and money-laundering offences.

"I am exceptionally proud of our New Zealand Police staff who supported Operation Trojan Shield," NZ Police Commissioner Andrew Coster said.

"It takes years to build these networks. Large-scale operations of this nature create enormous disruption and paranoia within organised crime groups because it breaks down their communication channels that they use to evade law enforcement detection."

Heavy police presence in West Auckland and Ōpōtiki

When he left he was spoken to by police and taken into custody.

Police have called a press conference in central Auckland this morning to discuss the "major trans-national organised crime operation".

In West Auckland, locals in New Lynn said they had seen police around Rua Rd and nearby Croydon Rd.

"Saw two unmarked police cars on Rua Road today - two cops with assault rifles stood at the end of the driveway by the crossing."

Residents in and around Whakatāne also reported seeing a heavy police presence in Ōpōtiki yesterday evening.

Staff at the News Whakatāne said they had received "multiple reports" of police there last night.

Overnight police raids around the world

The Herald Sun said Australian authorities worked with the FBI to monitor the a AN0M app that organised crime gangs used to plan executions, mass drug importations, industrial-scale money laundering and gun running.

Up to 4000 properties around Australia are said to have been raided by police.

Raids on AN0M users were carried out by authorities overnight - including in the US, the United Kingdom, Germany, the Netherlands and New Zealand.

Police told the newspaper that they foiled up to 21 murder plots and exposed the trafficking of billions of dollars worth of drugs into Australia.

More than 100 people have been charged, 3366kg of drugs and $35.8 million in cash seized, the Herald Sun reported. Up to 72 firearms were confiscated.