Twelve people linked to the Head Hunters and Mongrel Mob have been arrested as more than $8m worth of drugs and 17kg of 'P' were seized in a large-scale bust in Northland.

Operation Freya - a joint operation between police and Customs - saw 11 search warrants executed on Friday across Morningside, Rāwhiti, Ruakākā, Whananaki, and Rotorua.

More than 20 police cars - including Armed Offenders Squad (AOS) vehicles - caught the attention of the public as they rushed towards Bream Bay shortly before 10am.

A large contingent of officers were seen at an industrial address on Kepa Rd in Ruakākā and an address on Takahiwai Rd in One Tree Point.

In Whangārei, Morningside Rd was blocked by police near The Korna Store dairy while AOS officers escorted a shirtless man in handcuffs from the scene.

Overall, 17kg of methamphetamine was seized, as well as 5.44kg of MDMA and pseudoephedrine - all with a combined street value of $8m.

Assets worth around $240k that included a motorbike, boat and vehicles were confiscated by police under the Criminal Proceeds (Recovery) Act.

Around $70k in cash and a quantity of methamphetamine along with two firearms and ammunition were also seized.

Detective Inspector Bridget Doell said the bust had prevented around $25m worth of social harm across Northland.

"Methamphetamine use is unfortunately a major driver of crime across the Northland district."

Eleven men, aged between 27 and 56, and a 25-year-old woman were arrested, with further apprehensions a possibility.

They are due to appear in the Whangārei District Court on November 13 to face a raft of charges linked to the importation, manufacturing, and supply of methamphetamine.

Other charges include conspiring to import methamphetamine, MDMA and pseudoephedrine as well as participating in an organised crime group.

The joint investigation had led authorities to Ruakāka where they identified an alleged criminal syndicate with key leaders in the Headhunters Motorcycle Gang and Mongrel Mob

Doell said their offending was spread across the country.

"Ultimately, they have allegedly tried to import, manufacture or on-sell drugs into the Northland market, which currently has some of the highest drug use per capita wastewater readings in New Zealand."

For the past six months, the Northland District Police Organised Crime Unit led Operation Freya to investigate the smuggling of drugs from international destinations - including Africa - and the subsequent sale and supply in New Zealand.

It stemmed from seizure information Customs shared with police that showed several drug packages were destined for Northland.

Between March 2020 and June this year, Customs intercepted 15 separate air cargo or mail consignments with concealed drugs hidden in the likes of books, clothing, framed art.

The huge blow to the "sophisticated drug dealing and smuggling operation" would have a positive knock-on effect on crime in Northland.

"Drug users are known to commit high volume crimes - such as car thefts, burglaries, and fraud – in a bid to fund their drug habits," Doell said.

"Criminal groups hurt communities by exploiting people's drug addictions – profiting as they did so. They have little regard for the devastation or harm caused to vulnerable people in our community who are addicted to drugs."

Doell said police will continue to target people illegally profiting from the sale of illicit drugs.

They would continue to prosper communities that could come forward and seek help for family members and loved ones involved in drug use and criminal activities.

Customs Group Manager Intelligence, Investigations & Enforcement, Dana McDonald, said they worked closely with global law enforcement partners to disrupt the transnational movement and supply of controlled drugs and the harm it causes.

"Organised criminal groups may think that law enforcement doesn't care about small drug packages – but it all adds up, and it's only a matter of time before they are held to account."

"Customs actively targets all risk shipments – via sea, air or mail – and is determined to work with our partners, both here and offshore, to make maximum impact in dismantling the organised criminal groups that are involved," McDonald said.

"We want to help build resilient communities that thrive in the absence of illicit drugs and drug-related offending."

Police encourage anyone with information about suspected drug dealing in their community to contact 105, or Crime Stoppers anonymously via 0800 555 111.