The incident involved about 15 people outside the Justice and Emergency Services Precinct on Lichfield St.
Detective Sergeant Colin Baillie said they were from an “unknown gang”, trying to enter court to see someone they knew appearing.
Baillie said they were not allowed in because of the alert level 2 rules.
About six police officers and four security guards responded to the incident and two of the people involved were arrested.
Said Baillie: "I was there. It was members of an unknown gang trying to gain entry to the courts for proceedings.
"They were not allowed in due to Covid-19 rules, and some of them were exhibiting signs of intoxication or otherwise.
“The court staff, rightly so, wouldn’t let them in and police were called to quieten things down,” he said.
In July, a Mongrel Mob member’s head was stomped on several times, leaving blood on the pavement, during a fight with members of the Tribesmen gang at the district court.