Several people were injured in the fight at a hotel on Maitland Road in the suburb of Islington in the early hours of Saturday morning.
Police say a 21-year-old man suffered facial injuries when he was assaulted by Nomads members.
They say several men and a woman also suffered minor injuries when they came to the man's aid.
Detectives say the Nomads then left the hotel with an unknown man.
They want to speak with two men in relation to the brawl.
One is described as being of Caucasian appearance, about 40 years old with a large build, shaved head and goatee beard.
At the time he was wearing a blue shirt and jeans.
The other man is aged in his late 20s, with a medium build, brown hair, facial hair and tattoos on his neck.
He was wearing a black long-sleeved shirt with a Nomads insignia on both arms.