Melb youth Halloween party turns violent

Youths turned on police and two "substance-affected" teens were hospitalised after authorities shut down an underage Halloween party in Melbourne.

Emergency services were called to the party held at the Uniting Church in High Street, Northcote at 9pm on Monday following reports of underage drinking, drug use and fighting.

The Halloween 2K16 party - organised by the Darebin FReeZA Committee, a state government initiative - was supposed to be fully supervised.

Police say a number of people in the crowd, believed to be 500-strong, became violent and threw objects at officers when police and paramedics arrived.

Up to 30 local police originally attended, but extra officers and the dog squad were brought in, North Metro District acting commander Tim Hansen told reporters on Tuesday afternoon.

He said two substance-affected youths were treated at the scene and two others were taken to hospital.

Ambulance Victoria told AAP the two teenagers were taken to The Austin Hospital in a stable condition.

Acting commander Hansen said no one had been charged, but no specific offences had been reported to police.

A Facebook page advertising the night - which charged $2 entry for people dressed in costume and $5 for those who didn't - said the party would return "stronger than ever" and that it would finish at 10pm.

Partygoers have since posted on the same page describing the night as "hectic" and "so lit".

One posted a meme with the words: "Me: Mom I'm going to a party later. Mom: Do you have a ride home. Me:" and then a picture of someone being loaded into an ambulance.

Trams along High Street were impacted as police shut the road while breaking up the party.