Magistrate Clare Farnan agreed with prosecutors that Ahmed Elomar's presence in a group of protesters who tried to break police lines represented a threat to public safety, the Australian Broadcasting Corp. reported Tuesday.
Police said Elomar was among a group who pelted police with bottles and other objects Saturday during a protest in which six officers and 17 other people were injured.
Elomar, 29, pleaded innocent to taking part in a violent public disturbance while out on bail for driving offenses.
Farnan said Elomar would remain in custody until his next court appearance.
Leaders of Australia's Muslim community called for calm Tuesday and said further protests should be called off.