An out-of-control party of up to 200 youths ended in fights and disorder in a Dunedin park on Saturday night.
A party intended for 20 friends in Mosgiel swelled to around 200 people aged 15 to 17 through word of mouth, police said.
A parent in charge had hired security guards for the event but shut the party down around 11pm when it got out of control.
Young people spilled on to the streets around Oban Ave and Reid Ave and into Memorial Park.
Police said fights broke out, bottles were smashed and there was "general disorder".