Waikato police who had to deal with a major brawl at a party overnight say people should not use social media to publicise parties.
The party, which was publicised on facebook spiralled out of control in the Hamilton suburb of Melville last night.
Around 500 people turned up at the party and some of them pelted police with bottles when they tried to wind it up.
Fourteen people were arrested.
Senior Sergeant Andrew O'Reilly said the owner of the property had asked police to close the out-of-control party. He said partygoers gathered in the street and started to throw objects at officers, as well as starting several fights among themselves.
Mr O'Reilly said further callouts were received over the following hours as various groups continued to cause problems in the area.
Senior Sergeant Peter van de Wetering said dealing with the party was difficult.
"It wasn't an easy matter, there was hundreds of young people there, it took virtually all of Hamilton's resources that were working at that time in the morning and we brought in extra police from Ngaruawahia, Morrinsville and Cambridge as well."
Mr van de Wetering said when people publicised parties on social media they could never be sure who would turn up.
He said open social media was not the way to safely extend an invitation to friends because the person had no control over that information.