Yesterday 170 Crime Gangs officers raided 20 homes and arrested 12 "patch" members or associates of the outlaw clubs who, police say, took part in a brawl at the City Nightclub, Hindley St, about 5am.
They were charged under the Aggravated Riot laws that carry a maximum penalty of 10 years imprisonment.
The brawl took place just hours after the United Motorcycle Clubs staged a ride south of Adelaide to mark unity between bikie clubs.
Crime Gangs officers yesterday warned bikies not to seek reprisals and appealed to those associating with bikies to walk away before it was too late.
"Unless you want a life of violence, a life of crime where you are going to get a lot of attention from police and other gangs, I suggest you cut all ties to the club before it's too late," Detective Inspector Steve Taylor said. "The reality is, there's always opportunity for retaliations or reprisals, but the message is very simple from police ... (don't) engage in any sort of behaviour because we have a number of strategies in place to mitigate any risk."
Police say Sunday's brawl was sparked by a fight between a Hells Angels member and a Finks bikies outside The Firm nightclub, North Tce, an hour earlier. Both were arrested and charged over the fight.
The subsequent brawl, between 25 bikies, left four men in hospital - including one who had 16 staples in a head wound - and was captured on security vision handed to police.
Police say they uncovered a cache of weapons - including crossbows and knuckledusters - and illegal drugs, including amphetamines and steroids at the Finks' clubrooms and $16,500 in cash.
Insp Taylor said the violence was common among bikies.
"It's a stark contrast to the image (bikies) portrayed the day before with the (clubs) run when they portrayed an image of one of unity and camaraderie," he said. "The face we saw on Sunday morning is what we say is the true face of bikies."
The accused men were bailed to appear in court later.