Three Hong Kong protest leaders have surrendered to police as they try to take the protests off the streets after more than two months of rallies punctuated by violence.

Benny Tai, Chan Kin-man and Chu Yiu-ming quickly emerged from the station on Wednesday, 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.

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.

Police statement

Tai told the AFP news agency 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.

The three Occupy founders were joined in their "surrender" by 82-year-old Cardinal Joseph Zen, a prominent pro-democracy supporter, while 40 others also waited outside the police station to fill out forms to turn themselves in.

Students still occupy two sites after clashes with police earlier this week as they tried to surround city government headquarters.

Police said on 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."

Election reform demands

Protesters have camped out in commercial districts of Hong Kong for months, demanding China's government scrap its requirement that candidates in the 2017 election be approved by a panel chosen by Beijing.

China refuses to budge on the issue of candidate screening, and Hong Kong's leader Leung Chun-ying has warned that the protests are "in vain".

On Wednesday Leung rejected a call made by three students on hunger strike for a relaunch of the constitutional reform process.

The surrendered trio founded Occupy Central with Love and Peace, which aimed to shut down streets in the financial hub to press for free elections. 

The civic movement's campaign was overtaken by student protesters, who make up the bulk of the activists and who kick started their own protest by occupying the streets outside the government complex.

In response, the Occupy Central founders scrapped their original plan and announced they were joining the students on September 28.

Source: Agencies