Opposing bikie gangs are likely responsible for a brawl involving about 20 people, which broke out in Sydney's inner west, police say.
The fight broke out in front of a coffee shop on Burwood Road, Burwood about 8.30pm on Wednesday, and police were called.
Burwood duty officer Mark Scifleet said some witnesses saw people running from the area wearing bikie identifiers.
"Some were wearing Rebels ... jackets and that sort of stuff," he told AAP.
"From that, we've pieced together (it's) probably between the Lone Wolves and the Rebels."
A 39-year-old bystander waiting for a bus nearby was hit in the head with a glass bottle thrown during the melee.
Acting Inspector Scifleet said police would view CCTV footage from numerous Burwood Road businesses and are calling anyone with information to come forward.
They are especially keen to talk to a man described as Mediterranean or Middle Eastern, 175-185 cm tall with a dark beard.
He was last seen wearing a brown-hooded jumper.
