Police have stormed about 43 properties in Kawerau, Whakatane and Opotiki as part of a drug bust that resulted in 25 arrests.
One of the households targeted was owned by the president of the Kawerau Mongrel Mob.
The 20 men and five women arrested so far will face charges including possession for supply and supplying methamphetamine and cannabis.
Firearms, methamphetamine, cannabis and cash have been found at a number of addresses.
Police seized assets including boats, jet skis, motorbikes, firearms and vehicles.
The raids were the result of a six-month investigation into organised crime and the distribution of illicit drugs in Bay of Plenty.
Operation Notus was launched in October after members of the community contacted police with concerns about the social harm being caused by an organised crime group operating in the area.
The investigation found that members and associates of the Kawerau Mongrel Mob were involved in the commercial distribution of methamphetamine and cannabis.
Eastern Bay of Plenty Area Commander Inspector Kevin Taylor said the investigation required significant work from district staff and the National Organised Crime Group (NOCG).
More than 300 staff were involved in today's raids, including Bay of Plenty staff, NOCG, Armed Offenders Squad and the Asset Recovery Unit.
In addition to the Bay of Plenty raids, two properties in Gisborne and Hastings were also searched.
Taylor said the gang had been "preying on our community" and profiting from their own whanau and friends' addiction through the distribution and supply of drugs.
"They have shown that they put profit above all else and have a complete disregard for how destructive methamphetamine is to the health and wellbeing of users.
"We are committed to protecting our communities from the harm caused by organised crime and today's arrests will go a long way to disrupting the supply of methamphetamine and cannabis in Kawerau and wider Bay of Plenty region.
"A major focus for us is to work closely with iwi and our partner agencies to offer advice and support services to victims of this group, and those who have been identified as users of these drugs."
The police knew that family harm, addiction and neglect go hand-in-hand with organised crime and drugs, he said.
"As part of this operation we are working with Iwi and staff from Oranga Tamariki to ensure the welfare of children and other vulnerable people living at these addresses.
"A hub has been set up today to provide these families and children with access to support services."
Earlier today Kawerau mayor Malcolm Campbell told the Herald he welcomed the police raid and called it "a wake-up call to the gangs".
"This [gang and drug] activity has been going on in the whole of eastern Bay of Plenty long enough."
This morning's raids come a week after police arrested three people linked to the Barbarians chapter of the Mongrel Mob in Opotiki on methamphetamine offences.
In the past 18 months, a number of criminal investigations in the eastern Bay of Plenty have involved members of the Mongrel Mob.
A national survey of drug users found the Bay of Plenty had the highest number of people dependent on cannabis in the country, and high levels of methamphetamine dependency.
Thirty per cent of the people surveyed in the Bay were addicted to methamphetamine.
The Massey University survey also found the region had the highest need for help for substance abuse.