U.S. rapper Necro has been fined $3,000 Australian ($2,400) and ordered to pay court costs for his part in a brawl on the streets of Perth.

The Perth Magistrates Court was today (June 5) told the victim's cheekbone was fractured when he was punched several times by Necro on Thursday morning outside a cafe in central Perth.

Necro, 31, whose real name is Ron Raphael Braunstein, and Christopher Catenacci, 32, a DJ on his touring party, pleaded guilty to assaulting the 27-year-old man.

Defense attorney Michael Tudori told the court that the altercation sparked off when the victim said, "What the fuck are you looking at?" Braunstein responded, "What's your problem, I'm not looking at you... I can look at whoever I fucking want."

With Catenacci joining in, the scuffled spilled onto the street and ended up in a nearby convenience store.

Necro's arrest later in the day forced the cancelation of his Perth concert, which was due to take place Thursday night at the Hyde Park Hotel. Catenacci was fined $2,000 Australian ($1,600) for his actions.

Magistrate Richard Bayly told the pair they had 24 hours to pay up their fines before they could consider moving on to Adelaide, where the rapper's Australia tour is due to conclude with a Friday night show at the HQ venue.