Ashburton's mayor says mass gang arrests and the biggest local drug bust in over a decade won't damage the community's reputation as a safe place to live.

That's the view of Ashburton Mayor Neil Brown in the fallout from the three-day police operation, which would have shaken many in the community after 18 people were arrested and 160 charges laid.

One man faces more than 60 charges alone of supplying methamphetamine in an operation that saw 29 search warrants executed.

Those arrested were all from Ashburton and mainly associated with the Mongrel Mob. Others had links to Mangu Kaha, Highway 61 and Headhunters gangs and most were due to appear in court in Ashburton or Christchurch this month.

The arrests and seized cash, goods and drugs, including LSD and cannabis, would have made for grim reading for many members of the public in what has traditionally been a quiet regional town.

"These raids make it a safer community,'' mayor Brown stressed.

"Crime is in every community and the police are doing their job to keep our community safe.''

But Brown was concerned to find out about the significant amount of gang activity in his community, highlighted by the number of arrests and charges laid.

"Having that number of people in town that they picked up in one go, that is quite concerning, and the harm that it causes is quite alarming."

Brown wanted to remind the community to always be vigilant and report any suspicious activity to the police to help weed out all crime.

"Someone must know that this activity is happening, so they need to do the right thing and let the police know and stamp it out of our community."

It took more than 100 police officers from Ashburton, Christchurch and Timaru, including an armed offenders' squad, a specialist search group and dog units, to make what has been called a "huge blow" to the meth industry in the region.

The raids across the three days were part of Operation Cobalt, the national police campaign targeting organised crime and unlawful gang activity.

Some of the searches were carried out near Fairton School just north of Ashburton, but the pupils and staff were none the wiser and never in danger.

Fairton School principal Mike Hill also said they had no idea that residents with gang and drug connections lived in the small community, but he was happy to see them removed.

"If they keep to themselves, you never know they are there.

"They are in every community," Hill said.

- Daniel Alvey, guardianonline.co.nz