More than 30 arrests have been made in the Nelson Bays region in a national operation targeting indoor cannabis growers and cannabis dealers.
Nationally, police seized and destroyed more than 130,000 plants and more than 280 kilograms of dried cannabis during the six-month operation.
In the Nelson Bays region, 33 arrests were made and 321 plants and 6.5kg of cannabis seized.
Police targeted drug dealers working out of houses, aided by Operation Kelly, which used aerial searches to spot cannabis crops during the growing season.
In the Nelson-Marlborough region, Operation Kelly resulted in 3752 plants being seized and 52 arrests, including three related to gangs.
Firearms were also found, seven in Operation Kelly and 11 in Operation National in Nelson Bays.
Police said that as well as arresting 2573 people nationally, they confiscated 280kg of cannabis with an estimated worth of $5.6 million, and destroyed more than 130,385 plants and seedlings with a potential street value (at maturity) of up to $130m.
Detective Inspector Paul Berry said police found multimillion-dollar operations when they raided homes, including one run by a Wellington grandmother and her family, and one by a Southland resident who had accumulated millions of dollars in assets despite being unemployed for more than 20 years.
Every gang in the country was involved, including the Mongrel Mob, Head Hunters and Rebels, Mr Berry said.
"This is bread and butter for the gangs. This is how they make their money."
Police also found 248 children who would have watched their parents grow drugs and sell them at the door, he said. Many of those children had been referred to Child, Youth and Family.
By targeting cannabis growers and dealers, police estimated that $350m worth of harm had been prevented.
Police also discovered more than 300 firearms and other illicit drugs, including 1.4kg of methamphetamine, 321 LSD tabs and 4150 ecstasy pills.
They seized 14 properties, worth a total of $4.6m, eight cars, a boat, and cash and bonds worth more than $1m, some of which was seized under the Criminal Proceeds Recovery Act.
"When you put the two lots of results together - both Operation National and Operation Kelly - that is a significant disruption to the supply chain," Mr Berry said.
No-one was arrested for smoking cannabis - instead, people who were manufacturing and selling the drug and profiting from it were targeted. Many of those arrested have already appeared in court.
Operation National was just the start of a nationwide crackdown, Mr Berry said.
"We remain committed to disrupting the business end of illicit drugs - that means targeting the growers and the dealers."
By targeting dealers, police believed they were directly hurting the potential for organised criminal groups to operate successfully.
All 12 police districts were involved in the operation.
A recent United Nations report said New Zealand had one of the highest rates of cannabis use in the world.
Operation National, Nelson Bays
Targeted indoor growers and cannabis dealers
39 search warrants
321 plants recovered
6.5kg plant material
11 firearms and ammunition found
Operation Kelly, Nelson-Marlborough
Involved aerial searches to spot cannabis crops
5.5kg other cannabis
52 arrests, 3 related to gangs
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