Four arrests were made in Oamaru over the weekend as part of an exercise to target alcohol-related crime.
Southland and Otago Police increased presence as part of Operation Unite to raise awareness of the harm alcohol had on communities.
Southern District Senior Sergeant Craig Brown said four people were arrested on Saturday night in Oamaru.
Three of the arrests were for disorderly behaviour and one for breach of liquor bans, he said.
Oamaru Police Sergeant Ewen Graham said he was a bit disappointed with youth not respecting the law in regards to alcohol on Friday night.
He hoped doing this sort of operation would make a difference to the community, he said.
There was one licensed premises in Oamaru that he was looking into, Sergeant Graham said.
Over the weekend, there were 27 arrests in the Southern District: 14 were for disorderly behaviour and three for breaching liquor bans.
About 2100 motorists were stopped and breath-tested and 11 people were further processed for drink-driving.
About 80 licensed premises were checked for compliance with the sale of liquor act, with 30 licensed premises subject to a controlled purchase operation over the weekend.
Four of those were subject to failures, which related to sale of alcohol to a minor.
By RUBY HARFIELD