Sydney wedding brawlers won't talk to cops

Dozens of Sydney wedding guests involved in a brawl are refusing to speak to police, who are now appealing for public help as they piece together the wild fight.

The melee broke out between around 30 people outside a Riverwood reception centre late on Saturday night.

A 22-year-old man found semi-conscious was hospitalised with facial injuries, while a passing motorist had his car window shattered during the brawl.