A bunch of search warrants across the Tasman District uncovered thousands of cannabis plants, drug utensils and firearms in a fortnight-long bust.
Inspector Dan Mattison says the search was aimed at reducing social harm in the regions.
"The supply of illicit drugs has a big impact on our community. People are committing dishonesty crimes such as burglary to fund their habit," Insp Mattison says.
Dozens of public and private land plots were searched; the largest individual seizure was 400 cannabis plants off a public plot on the West Coast.
All of the plants were destroyed following their seizure.
An indoor growing system was also found, along with firearms, one of which was loaded and illegal, $1700 in cash, and methamphetamine and cannabis utensils.
Fifteen people are facing charges, two were given warnings, and West Coast police are looking to speak to four people.