Three boys have been robbed and assaulted as they were leaving a massive party organised on Facebook in Melbourne where a riot later broke out with police.

The trio, all aged in their late teens, left the party in Glen Waverley about 11pm (AEST) on October 4 and in a nearby street were approached by a group of six to 10 men.

The men allegedly assaulted the boys, leaving them with serious injuries including a punctured ear drum, and stole their wallets and phones.

Police believe the men also attended the party and would like to speak with anyone who may have seen them.

Up to 400 teenagers clashed with police after partygoers set off fireworks and gatecrashers showed up at the Glen Waverley house.

About 700 people had been invited to the party, mostly through Facebook, according to a group of youths who returned to the house on Saturday.