Police investigate Sydney casino brawl

Two men have been hospitalised after a brawl involving two groups of people outside Sydney's Star Casino.

Police are investigating the incident, which occurred about 1.25am (AEDT) Saturday on Pirrama Road, Pyrmont.

Two men, aged 24 and 44, were taken to St Vincent's Hospital with non life-threatening injuries after the fight.

Police believe the brawl started when one group was barred from entering the casino.

It's alleged a man was headbutted and that started the fracas on Pirrama Road.

Police spoke to 12 people at the scene and investigations continue.