Trio charged after fight on Sydney bridge

Three males have been charged after a fight on Sydney's Pyrmont footbridge left a man with a stomach wound.

Police say two groups of men clashed on the bridge at about 1.50am on Tuesday, leaving a 26-year-old in a Sydney hospital with a large cut to his abdomen.

The alleged attackers, two boys aged 16, and a 19-year-old man, then ran from the scene but were later found near Central Station along with an accompanying woman.

All three males have been charged with reckless wounding in company and affray and are expected to face Sydney courts later on Tuesday.

Police don't know what caused the clash or how the 26-year-old was injured.

"I can't tell you what the weapon was, we're not exactly sure at this point in time," Acting Inspector Steve Hodges told reporters in Sydney.

Act Insp Hodges said the area where the attack occurred was outside of the lockout laws.

"Whether that has a factor I can't comment on," he said.

Tuesday's alleged attack follows a brawl involving two groups outside the Star Casino on February 13.