Police are investigating how a large group of underage teens came to be intoxicated at a Taree function centre overnight.
Officers were called to the venue on Beeton Parade just after 9.30, following reports a crowd was out of control.
Police were confronted by up to 300 partygoers, with two officers allegedly assaulted as they tried to break up the crowd.
Five teenagers were arrested and charged with offensive behaviour, and assaulting police.
One resident says the party was advertised on Facebook.