Twenty-nine people have been arrested, including a senior Waikato Mongrel Mob member, after a three-month police investigation resulted in 20 search warrants being executed this week.
Operation Kingsville was carried out in Waikato, Auckland and Bay of Plenty, and resulted in four methamphetamine labs being closed down, police said.
Property, vehicles, jewellery and cash valued at over $1 million has been siezed, as well as loaded guns, meth and $200,000 cash.
Those arrested face charges including participating in an organised crime group, money laundering and the manufacture and supply of methamphetamine.
Sixteen of those charged as a result of Operation Kingsville have been remanded in custody.
The remaining 13 will reappear in the Hamilton District Court in the coming weeks.