Three carloads of Southlanders were involved in a fight in Cromwell on Saturday night, Constable Maude O'Connell said.
Police attended a fight on the forecourt of BP2Go at 6.30pm and another between the same group of people later that evening in the Cromwell Mall car park.
"It was all out-of-towners and the incidents were alcohol-fuelled," Const O'Connell said.
Those arrested were aged from 20 to 25.
They face charges of disorderly behaviour, wilful damage and assault.
Sergeant Paul Crosswell, of Wanaka, had a blunt warning for others considering travelling to Central Otago to cause trouble.
"They seem to be young men with limited intelligence coming to Central Otago not to enjoy themselves, but to cause mischief.
"That behaviour is not going to be tolerated. They can turn around and go home. We don't want them here."
The volunteer Otematata Fire Brigade was called out five times to the campsite near Loch Laird to extinguish fires lit by young people in defiance of a total fire ban.
About 60 tents and an estimated 130 young people were camped there on Saturday night.
Bottles were thrown as the fire brigade left, denting their vehicles.
Bottles were also thrown at police vehicles during patrols of the campsite.
The behaviour prompted Otematata fire chief Mike Thomas to yesterday threaten the brigade would not turn out if summoned last night to extinguish fires at the campsite, unless property or life was clearly under threat.
"I'm not going to put my people and my equipment at risk again," he said.
Sergeant Wayne Brew said it was "loutish behaviour".
"It's not our job to babysit kids for parents who send them off to Otematata," he said.
Young people ran amok in Otematata on Saturday night, smashing bottles, with one group jumping on the roof of the public toilets.
Broken glass was scattered in the public toilets, smashed against the toilets' outside walls, in the children's playground and on the sports field.
Local residents picked up as much glass as possible, but were becoming increasingly angered.
Mr Thomas said the brigade received the first call-out to Loch Laird about 8.30pm on Saturday. It was followed by another four calls, the last at 1.40am yesterday.
Each time, two units went out with nine firefighters.
He said bottles were "smashed everywhere" at the campsite and were thrown at the engines.
"The trouble is, young ones see things like the Undie 500 on TV and scarfies getting away with it, so they do the same thing," Mr Thomas said.
"While we were driving away, one of them yelled out: 'We'll see you again soon'.
"All of us are volunteers and we have to put up with this during a holiday weekend."
Ahuriri Community Board member Graham Sullivan, who was out helping with cleaning up yesterday, said enough was enough.
He intended to bring the issue up at the next board meeting and wanted to discuss options to quell bad behaviour, including a temporary liquor ban and a bigger police presence with zero tolerance for young offenders.
Three police had been seconded to Otematata for the weekend, with support from Kurow and Omarama police.
Labour Weekend has traditionally been the time when families head to the Waitaki lakes for the first big weekend of the holiday season.
But the family atmosphere in recent years has been ruined by the behaviour of some young people.
This year, before Labour Weekend, warnings were sent to the three Oamaru secondary schools, saying young people would be evicted from camp sites and served with trespass notices if they misbehaved, lit fires or drank alcohol while under age.
Sergeant Wayne Brew said about 130 young people from South Canterbury and North Otago aged between 15 and 25 years were at the camp site, although it was hard to tell accurately in the dark.
He estimated 15 to 20 young people were causing the trouble.
The problem police and firefighters faced was identifying, or even seeing, offenders in the dark.
On one occasion, while police were there, there was a fight within 30m of them, but they were unaware of it.
On Saturday night, a 16-year-old Oamaru secondary school student was processed for driving over the legal blood-alcohol limit and a man in his 20s was evicted from the camp and served with a trespass notice.
Mr Brew said police patrolled the area in vehicles and on foot between 10pm on Saturday and 1am yesterday.
While they were there, one person yelled out: "Let's start a riot."
