Hong Kong student protest leader Joshua Wong Thursday accused police of using violence against him during his arrest as authorities clashed with demonstrators at a flashpoint rally site.

The 18-year-old Wong and another student leader, Lester Shum, were taken into custody Wednesday as authorities moved in to clear the pro-democracy camp in the district of Mongkok, scene of some of the most violent clashes in nearly two months of rallies.

Wong, a key figure in the movement that has paralysed parts of the southern Chinese city, was charged with obstructing the work of police officers and released on bail Thursday.

"They (police) had pressed me to the ground to limit my movement and injured me in the process," he told reporters outside the Kowloon City Magistrates' Court.

"This caused injury marks to my neck and face and they consecutively, six to seven times, tried to hurt my body including my private parts," he said.

Shum, 21, also alleged police had used violence when arresting him.

"They had used fists to punch and feet to kick my body in the process. They had used their knees to bump me and kicked me in the waist," Shum, who like Wong was released on bail late Thursday, said.

"They had also pulled on my hair and pressed my head to the ground, this happened twice," he said.

News footage of the arrests did not appear to show the pair resisting.

Some 150 protesters were taken into custody when authorities tore down barricades and tents in Mongkok, one of three main protest sites, in a major blow to the movement.

Wong said he has been banned from the area for two months as part of his bail conditions.

"I can't go to the Mongkok area before January 14. I feel mystified," he said.

His lawyer Michael Vidler told the court that the "motivation for this prosecution is political".

Both he and Wong were pelted with eggs as they left the courthouse as tensions run high in Hong Kong over the future of the struggling pro-democracy movement.

Protesters have been calling for full democratic reforms that would allow them to choose who to run for the city's top post. Beijing says all candidates to become Chief Executive must be vetted by a loyalist committee.

The protests at times drew tens of thousands of people onto the streets.

But the crowds have dwindled markedly in recent weeks as the movement has struggled to maintain momentum and commuters have grown weary of transport disruptions.

A main road in Mongkok was reopened Wednesday following a two-day operation that saw chaotic scuffles between police and protesters.

But there were more scuffles between police and protesters late Wednesday as some demonstrators attempted to retake the main thoroughfare of Nathan Road.

Mongkok, a major shopping district on the Kowloon peninsula, had been occupied since the sit-ins began at three separate intersections in the city on September 28.