Police had to mop up after an out of control Mosgiel party spilled into the streets on Saturday night.
About 200 15 to 17-year-olds turned up to the party initially intended for about 20 guests.
Police said party-goers learned of the event by word of mouth.
Security guards engaged by the adult supervising the party shut it down about 11pm because of the number of people that turned up.
The "unwelcome teenagers" moved to Memorial Park were they started yelling, fighting, smashing bottles and causing general disorder, Acting Senior Sergeant Craig Dinnison, of Dunedin, said tonight.
Police were called in and two youths were arrested and taken home. The rest of the crowd dispersed once a police paddy wagon arrived from Dunedin.
Sgt Dinnison said the disappointing incident tied up five police staff for several hours.
As a result of the "drunken idiocy" and disorder Dunedin City Council staff also had to be called in to clean up a "vast" amount of broken glass and check and clear the area thoroughly, as a children's triathlon was being held there today.
"Police are extremely disappointed with the reckless behaviour of [these young people]".
If anyone had any other information about the incident, they were encouraged to contact the Mosgiel police, he said.
