Social media is used overseas to incite democracy and create revolutions - but in New Zealand it's used to organise "booze-fests", a victim of an out-of-control party says.
Hamilton City Councillor Ewan Wilson lives next door to where a party ended in a near-riot on Saturday night when 200 party-goers hurled bottles at police and ambulance staff.
More than 40 police - including the Waikato tactical response unit - tried to control the crowds at the Hammond St party.
The unruly revellers forced a medical crew to leave and people at a nearby event were placed in lockdown until the crowd was under control.
Mr Wilson called on the landlord to be held accountable for the tenants' actions.
"A party is okay managed responsibly. What occurred [on Saturday] wasn't," he said.
"Using social media with an open invite is reckless and careless and could have resulted in injuries.
"I look at the way social media is used across the world to incite democracy and create revolutions, and here in New Zealand they use it as a mechanism to organise booze-fests. I think that's bad, shortsighted and just plain dumb."
Mr Wilson said neighbours were made aware of the planned party after being shown its Facebook page. But he was unable to warn the hosts - a group of Waikato University and Sir George Seymour College students.
"I went to warn them of the dangers of hosting a party that could easily get out of control, but they were not home. By 11.30pm there were probably 250-odd people there in what is a really nice neighbourhood.
"Rather than everybody be contained to the property, they were spilling on to the street, they were noisy, they were quite vocal, the odd bottle was smashed.
"As it was approaching midnight I called police and noise control to say this is just not appropriate."
Inspector Karen Henrickson said four arrests were made, including one for assault with a weapon. No police or ambulance staff were injured.
She backed Mr Wilson's call for caution on social media sites, saying there were risks associated with using them to organise parties. Mrs Henrickson said a new police strategy called a Peak Load Roster was used to deal with the situation.
"Though the number of youths involved was quite large, police were able to control not just them but also successfully manage the Balloons Over Waikato and maintain a presence in the city's bar zone thanks to the additional staff provided at peak times as part our current rostering model."