They all appeared in the Invercargill District Court yesterday, each charged with participating in an organised criminal group between January 31 and September 18 last year.
The incidents included two drive-by shootings in Invercargill and incidents in February and April last year where seriously injured people were dropped off at Gore Hospital.
Some also faced firearms charges.
The arrests signal the end of Operation Pakari, an investigation which began last year into a number of serious offences believed to be linked to the Mongrel Mob in Southland, in particular the Mataura chapter.
By noon yesterday, 12 search warrants had been executed at properties in Mataura, Gore, Dunedin and Hamilton.
Eleven males aged between 16 and 43 were arrested.
"This operation has been about protecting the community and ensuring Invercargill, Gore and Mataura continue to be safe places to live," Southland area commander Inspector Mike Bowman said.
"These groups are not welcome here.
"We see the harm they inflict through organised criminal activity and we will target the people who seek to profit from that harm."
None of the defendants were granted bail yesterday.
An additional defendant appeared in the youth court in relation to the same matters.
All but two of the accused were granted interim name suppression.
Police said the arrests followed months of investigative work by Invercargill police as well as officers outside the district as part of the nationwide Operation Cobalt.
They said they had worked alongside social agencies to support families who may find themselves struggling following the warrants.
"It’s one thing to arrest a parent, it’s another to leave another caregiver struggling to support the family," Insp Bowman said.
It is understood more suspects will appear in the Invercargill District Court today in relation to the operation.
The Crown intends to make an application to have all the matters heard together in the High Court next month.
Police said they could not rule out more arrests.
