Police are still investigating how the party on Helen St spiralled out of control and resulted in police being pelted with stones when they arrived.

Two police cars were damaged and five officers sustained minor injuries at the event, believed to be an 18th birthday party.

Chief Inspector Danny Sharkey said police were increasingly being called to parties that had been promoted on social-networking sites, which he called the "Corey phenomenon."

Corey Worthington made headlines in Australia last year after he advertised his party on a social networking site MySpace, attracting more than 500 people.

The unrepentant host became a minor celebrity in the aftermath of the party, which caused $20,000 damage.

Many people are using new forms of technology to promote parties, even if it is not their own event.

"We were aware (the Helen St party) had been advertised and we did give advice about what they needed to do security wise," Insp Sharkey said.

"We're appealing for parents to sit down with their children and explain to them the dangers of firstly getting involved in things like that. We're also asking parents to have conversations with their teenage children about the consumption of alcohol, and to be proactive about where their children are."

Insp Sharkey said no charges had been laid after the party, but investigations were continuing.

Police also had to escort several intoxicated people home after the party.

"We are regularly being called to disturbances at parties, where there are gatecrashers and they cause trouble," Insp Sharkey said.

"If they're not allowed in they start causing trouble and damaging property, and this is happening right across the command. The other night was an exception because there were an extremely large amount of people."

For full coverage see Tuesday's Mercury.

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