The founders of Hong Kong's pro-democracy Occupy movement surrendered to police Wednesday in a symbolic move, as they try to take the protests off the streets after more than two months of rallies punctuated by violence.

Dozens of supporters, carrying yellow umbrellas which have become a symbol of the movement and shouting "I want true democracy without fear!", surrounded the trio as they turned themselves in at a central police station.

However Benny Tai, Chan Kin-man and Chu Yiu-ming quickly emerged from the station, saying they had not been arrested despite admitting "participating in unauthorised assembly".

"We have not been arrested so we are allowed to leave with no restriction on our liberty," said Tai.

He told AFP there were "political considerations" behind their swift release to avoid crowds flocking to the protest zones, but said it was inevitable they would eventually be arrested.

"I don't think the matter will be resolved on this occasion, later we may be arrested, even prosecuted for more serious offences," Tai added.

The three had been joined by 82-year-old Cardinal Joseph Zen, a prominent pro-democracy supporter, who also gave himself up.

About 40 other supporters waiting outside the police station also queued up to fill out forms turning themselves in.

"This is for the fortune of the next generation," said secondary school teacher April Fan, 55.

Police said Wednesday afternoon that 24 people had so far surrendered.

"They were explicitly told by the interviewing officers that illegal occupation of public places was an unlawful act and they should stop such act immediately," a statement said.

"Police will conduct follow-up investigations based on the information provided."

The founders' "surrender" and their call to end the road blockades followed violent clashes between protesters and police outside the government headquarters late Sunday which left dozens injured.

Tai said the Occupy movement would now take a different approach to promoting democracy, including through education and a new social charter.

Protesters began blocking three major intersections in late September to demand free leadership elections in the semi-autonomous Chinese city. One has since been cleared by police.

China insists that candidates for the 2017 leadership vote must be vetted by a loyalist committee, which demonstrators say will ensure the election of a pro-Beijing stooge.

China refuses to budge despite the student-led protests and Hong Kong's current leader Leung Chun-ying has also taken a tougher line since Sunday's violence.

On Wednesday he rejected a call made by three students on hunger strike, for the constitutional reform process to be re-launched.

'Pain for justice'

Leung's office said in a statement there was no legal way to restart the process.

"Expressing views on constitutional reform through illegal and confrontational means is bound to be futile," it added.

Public support for the protesters has waned. A survey last month showed 83 per cent of respondents want the road blockades to end.

Anti-Occupy demonstrators outside the police station swore and held up placards of the three Occupy founders in striped jail uniforms.

"Support the government to enforce the law!" they shouted, and "Eat shit!"

Analyst Sonny Lo said the Occupy trio were handing themselves in to "reignite" the movement by regaining the moral high ground.

"They are trying to turn public opinion back from a low point... they are trying to take responsibility and face possible legal charges" which could gain renewed sympathy from the public, he said.

Despite the Occupy call to retreat, the student protesters on hunger strike vowed they would continue "suffering pain for justice".

Teenage protest leader Joshua Wong and two fellow students, who began fasting late Monday, read out their emotional open letter to Leung from their tent outside government headquarters.

"We believe we are doing better by suffering pain for justice than you are by having big meals," they said in the letter, renewing calls for dialogue on political reform.