The FBI-led operation that saw the arrests of top gang members in New Zealand is forecast to put almost no dent in the high use of methamphetamine.

The New Zealand police laid 900 charges and arrested 35 people, including senior members of the Comancheros, the Waikato Mongrel Mob and the Head Hunters.

Assets worth $3.7 million, including two boats and more than $1 million in cash, were seized.

Criminals have also been netted across the globe in what's been called Operation Trojan Shield, after police tricked them into communicating on an app run by the FBI.

The University of Canterbury's director of criminal justice, Jarrod Gilbert, praises the cooperation between agencies in New Zealand and abroad.

But he doesn't think the sting will cut the supply of methamphetamine here.

"While there's demand for methamphetamine - as there is in New Zealand - and the price is high, we're always going to have this trade. Someone will always slip back into this void."

He says corruption in New Zealand is low and criminal takedowns like this could help it stay this way.

"What it means is [criminals] can't gain a really strong financial base, which will in turn mean that they don't have the money to start corrupting or buying off government officials or people in the ports and airlines that would make their operations efficient."

Louise Hutchinson, the Waikato Mongrel Mob's public relations spokesperson. Photo: RNZ / Andrew McRae.

Louise Hutchinson, the Waikato Mongrel Mob's public relations spokesperson, calls the way the police announced the bust a smear campaign against gangs.

"The police ... have that huge platform and then the mainstream media on top of that. We're up against it."

She says the organisation has a zero tolerance policy on drug dealing and tries to steer members away from a life based on criminal activity.

She says not all of the 35 people that were arrested are gang members and some are white collar criminals.

"Our politicians want to focus on the gangs, but this is widespread... But it's really easy for politicians and the police just to target us."

Gang expert Jarrod Gilbert. Photo: supplied

Gang expert Jarrod Gilbert doesn't think it's a smear campaign, but he says it's important to separate gangs from organised crime groups.

"Organised crime will come in a whole variety of forms, particularly when we're looking internationally. We have to be very careful in [being clear] it's not a gang issue, but an organised crime issue."

Waikato Mongrel Mob leader Sonny Fatupaito confirmed in a statement that police searched three member's homes on Monday afternoon as part of the operation and the three members have been arrested and remanded in custody.

He says his own home and the gang's headquarters have not been searched, and he was not detained for questioning.

Fatupaito says his zero tolerance stance against pedalling drugs is well known.

"My continued focus as a leader is to influence, educate and empower our members to choose to live positive, constructive, and productive lives free from alcohol and drugs, and steer them in a direction away from criminal offending."

Former gang member, Martin Kaipo. Photo: RNZ / Dan Cook.

Community organisation chief executive and former gang member, Martin Kaipo, thinks the crack down is a good thing in the midst of the social harm caused by gang activity and related drugs, such as meth.

"As soon as they put those colours on their backs the whole lifestyle and environment changes."

Meanwhile, Prime Minister Jacinda Ardern says the sting will have a big impact on the supply of meth and pointed to the number of people arrested and the plans that would be halted as a result.

-RNZ/Jean Bell.