Police executed 29 search warrants as part of a large-scale operation that resulted in 160 charges across Ashburton and 18 arrests.
Senior sergeant Leigh Jenkins, sub-area commander for Ashburton, says that the raids conducted this week will make a "huge dent" in Ashburton's organised crime syndicate.
"It's the biggest drugs bust in his area in more than a decade, and possibly the biggest of its type in Ashburton ever," said Jenkins.
One person alone has been charged with more than 60 offences of supplying methamphetamine.
Police executed numerous search warrants as part of Operation Cobalt across Ashburton this week. Operation Cobalt is a nationwide crackdown on illegal gang activity and is targeted at disrupting gangs.
"This should send a message that if you are involved in criminal activity in Ashburton, we will hold you to account," Jenkins said.
Police said along with those arrested, items seized include drugs with a likely street value in excess of $70,000, including methamphetamine, cannabis, LSD, and other restricted drugs.
$20,000 in cash was also recovered, including two shotguns, a crossbow, seven imitation firearms, ammunition, and a number of other restricted weapons and prohibited firearms parts.
Police said, "those arrested are all local to Ashburton and mainly associated with the Mongrel Mob, while others have links to Mangu Kaha, Headhunters, and Highway 61 gangs."
"I'm confident that these arrests will go a long way to helping ensure our community is safe and feels safe," said Jenkins.
Jenkins said the operation was a result of the community and Police recognising an issue that needed addressing, and the results are hugely significant.
"The harm these individuals peddle comes at huge cost to individuals and families in our community, not to mention the other offending – such as burglary – associated with drug harm."
Police from Ashburton, Christchurch, and Timaru, including public safety teams, armed offenders' squad, dog units, and the specialist search group, were involved in the operation this week.
Act Party leader David Seymour, who was visiting Ashburton on the first day of the operation, said communities such as Mid-Canterbury have lost their innocence when police have to swoop on Ashburton and execute search warrants across town as part of a pre-planned operation.
Jenkins wanted to remind the community that police rely on the community's support to help police clamp down on this offending.
"If you notice any suspicious behaviour, please let us know.
"Your information could be the piece of the puzzle we need to help bring offenders before the courts."