Community leaders in the Bay of Plenty hope police raids targeting the Mongols motorbike gang will reassure the public they are safe after months of escalating tensions.

But they say more must be done to crack down on the root cause of the tensions: methamphetamine.

Ten people, including the gang's senior leaders, were arrested in yesterday's raids and police seized military-style assault weapons, AK-47s as well as molotov cocktails, vehicles, drugs and cash.

Since January, there have been six shootings in the Bay of Plenty involving the Mongols and rival gangs.

The Mongols have also been linked to arsons, aggravated robberies, serious assaults and other violent attacks.

Tauranga Mayor Tenby Powell hopes yesterday's police operation will go some way to dismantling a major criminal syndicate in the region.

"The gang tensions were rising in the western Bay of Plenty.

"The methamphetamine trade, which is fundamentally what this is all based around, and the organised crime syndicates that are managing that trade are very active and they are jostling for position, they're fighting for turf."

Powell was alarmed by the arsenal of weapons seized by the police.

"In all honesty, I can say as a past military officer, I was speechless really to discover the access to those weapons systems, the ammunition that comes with them, and the ability that clearly they have to produce [improved explosive devices] of that level."

Community advocate and lifetime Black Power member Denis O'Reilly says gangs like the Mongols, established here by people deported from Australia, operate on an entirely different basis to the gangs the public is used to seeing.

"It's almost as if they've come in with COVID, they've come in with an infection and it's not conducive to community or whanaungatanga.

'It doesn't mean that potentially they're not good people, they're all New Zealanders by dint of having been exported here under 501, but they're not playing the game, they're not part of the team of five million."

Powell says police deserve credit for the Mongol crackdown but he's still worried about the uptick in violence linked to the 501s from Australia.

"We have not seen this level of activity prior to the 501s arriving. In an environment as small as western Bay of Plenty and the wider Bay of Plenty in some regards, with access to our number one port in New Zealand, I think it's time to have a conversation around how we stem the flow of methamphetamine into the country."

Ngāi Te Rangi chief executive Paora Stanley says research shows methamphetamine use in Tauranga Moana is higher than in other parts of the country.

He says the drug is having a devastating impact on whānau and he's involved in discussions to build a residential treatment centre for meth addicts.

"A lot of our energies, as an iwi, has to go into those types of treatment areas. The enforcement, the arrests and all that type of stuff is conducted by the appropriate authorities.

'The mess that has to be cleaned up. Methamphetamine is phenomenally huge and it's been getting systematically bigger over the last five to seven years."

The 10 people arrested in yesterday's raids face a total of 228 charges.

They include participating in an organised crime group, money laundering, conspiracy to deal methamphetamine, supplying methamphetamine, supplying cocaine, unlawful possession of firearms, and unlawful possession of explosives.

Police concerns

Detective Superintendent Greg Williams of the National Organised Crime Group told Morning Report: "I suppose the concern for us is some of the people being sent back here are in the top echelon of gangs and in the leadership of gangs in Australia. They still have a strong connection to those Australian gangs.

"You can see from the charges laid here and the types of weapons and the activity over the last few months that they are intent on trying to create a supply line through to communities for drug dealing and the like."

He says the weapons being seized did not surprise police.

"We have seen over the last three or four years a general arming up by the gangs. What's more concerning, as is the case here, the possession of those weapons and the clear propensity to use them ... it's incredible really, that no-one in the community was caught in the crossfire of these ongoing events.

"We have seen an expansion of the gangs - a number of the gangs have increased in size. Part of this is to do with the decrease in the price of methamphetamine and the ability for a lot of gangs to be able to deal it into these vulnerable communities, which is quite tragic.

"As these new gangs come in they are trying to squeeze into what is already a compressed market... What you have seen here is a classic example of gangs warring over that market and when we say that, that's to control these people who daily are having to buy methamphetamine."

The assets being seized by police were being used by gangs as marketing tools to attract new members.

"[These gangs] often sell themselves as cool, lots of bling, lots of flash assets, but really, behind it is quite significant violence and for a lot of these people joining these gangs, addiction as well."

-RNZ/Sarah Robson.