Police have seized firearms, vehicles, drugs and cash worth $2.5 million as part of Operation Cobalt targeting organised criminal activity in Palmerston North.
Six people were arrested after the searches were carried out on 8 November in Palmerston North and Auckland.
Among the vehicles seized were Harley-Davidsons, an Audi, a Range Rover, a BMW and a Ford Raptor.
About $560,000 cash was located, along with about 9kg of methamphetamine which police said had a street value of $1.6m.
Seven firearms were recovered along with equipment consistent with the tools needed to convert starter pistols into illegal firearms.
Central District field crime manager Detective Inspector Paul Baskett said the arrests and seizures would make a significant impact on the sale and supply of methamphetamine in the area.
"Operation Cobalt is continuing to target and disrupt illegal behaviour, such as the operation allegedly being conducted by this group," he said.
Four men, aged 32, 36, 45 and 55, and two women, aged 31 and 32, are due to appear at the Palmerston North District Court on 2 December on a number of drug-related and other charges.