About 200 textile workers, union members, land protesters and several monks attempting to rally at a Phnom Penh park were met by scores of riot police, according to an AFP reporter at the scene.
A brief clash broke out when some of the protesters tried to make it through police lines into Democracy Park, prompting security forces to use batons against them.
Protesters then responded by throwing rocks, water bottles and sticks.
At least 10 people from both sides were injured during the violence, according to activist Am Sam Ath of local rights group Licadho.
"The clash shows zero tolerance from authorities (to protest),'' he told AFP.
Authorities have quelled recent street protests against strongman Prime Minister Hun Sen.
The government says the rallies were illegal and has indefinitely banned demonstrations in the capital by the opposition - which accuses Hun Sen of vote-rigging in polls last year.
A protest organiser told reporters that they would press on with their bid to free those arrested earlier this month during a police crackdown on striking garment workers, which left at least four civilians dead.
The employees were demanding a minimum wage of US$160 (5,200 baht) a month for their work in an industry which supplies brands including Gap, Nike and H&M.
"Our activity today is not the final one. We are making a stand and we will not stop our demands,'' said union leader Ath Thorn.
The 23 people arrested in connection with the unrest are being held at a prison near the border with Vietnam on charges linked to the incident.
Cambodian police broke up a rally in the capital Tuesday and briefly detained 11 activists who were calling for international assistance to secure the release of protesters.
Hun Sen faces mounting criticism by rights groups of his government's suppression of street protests intended to challenge his nearly three-decade rule.
He has faced accusations by rights groups of excessive force against the garment workers as well as against the opposition.
The main opposition party has boycotted parliament since the polls but 61-year-old Hun Sen, who has vowed to stay in power until he is 74, has refused to step down or call a new election.