Blue Mountains police were informed the party for 150 guests had been organised to take place at Warrimoo Community Hall. Three security guards had been hired to manage the party.

But police received intelligence from social networking pages which indicated a large number of gatecrashers were planning to attend the party.

Officers from the public order and riot squad were organised to patrol the venue and were forced to break-up a brawl between large numbers of gatecrashers outside the venue about 10.30pm.

Police then shut the party down and moved the group on. They charged two boys, aged 16 and 17, in relation to a later fight at Warrimoo Railway Station.

Officers were also forced to use capsicum spray to control a fight between a group of teenage girls, which occurred in the area after the gatecrashers had been moved on.

Inspector Max Wallace from Blue Mountains Local Area Command said that had police not been informed of the party the situation could have been much worse.

“Having the organisers give police early notice of their party has enabled us to have the appropriate resources available to handle the situation,” he said.

“It is a concern, however, that there continues to be a minority of young people who go out with the sole intention of getting drunk and violent.”