Hong Kong police dismantled the city's main pro-democracy protest site Thursday, clearing tents and barricades after more than two months of rallies and arresting more than 200 demonstrators, who vowed their struggle lives on.

Hundreds of police moved in from all sides of the Admiralty camp in the heart of the business district, sweeping away shelters and supply stands before swooping on a core group at the centre of the site, including student leaders and lawmakers.

As police cleared the last handful of protesters late Thursday, parts of the site reopened to traffic for the first time since September.

Those making a last stand were the remnants of what once numbered tens of thousands of people at the height of the protest movement, before public support waned.

The call for free leadership elections has underpinned the demonstrations, and protesters have vowed the clearance operation will not end a campaign they say has redefined the city's vexed relationship with Beijing.

Some were carried by groups of four officers while others were led off on foot, one by one. Those who remained lay on the road shouting, "We are peaceful", "We will not resist" and "I want true democracy".

In all, 209 people were arrested for "unlawful assembly and obstructing police in the execution of their duties", police assistant commissioner Cheung Tak-keung told reporters in a briefing late Thursday.

Protest group Hong Kong Federation of Students (HKFS) said that nine of its members had been arrested.

Media mogul Jimmy Lai, a fierce critic of Beijing, and veteran campaigner Martin Lee were among those led away -- Lee holding up a victory salute to reporters.

Singer Denise Ho shouted "Civil disobedience without fear", as she walked away with officers while lawmaker Claudia Mo sang "We will overcome" and shouted "We will be back" through a megaphone before being escorted off.

Student leaders Alex Chow, Nathan Law and Eason Chung were also take away by police, alongside other protesters including an elderly man in a wheelchair.

"This is not the end of the movement. The political awakening amongst the young is irreversible and we will fight on," Mo told AFP earlier Thursday.

Lee added: "In the heart of every student who has participated in this movement there is now a fire burning, a fire for democracy. This fire cannot be extinguished by an iron fist."

Earlier in the day, police had announced a "lockdown" after a 30-minute window allowing protesters to voluntarily leave the site -- an encampment of tents, supply stations and art installations sprawling along a kilometre of a multi-lane highway through the Admiralty district.

Some managed to leave after the deadline, but were asked to give their identity details to police.

- 'The start of something' -

Thousands gathered on Wednesday night for one final mass rally at the site, but the numbers had already dwindled to hundreds by Thursday morning.

Before the police operation, bailiffs descended with cutters and pliers to take down barricades and load them into trucks to enforce court orders taken out by transport companies frustrated at the long-running disruption.

The Admiralty site has been the focal point of the protest movement since rallies erupted in September, after China's Communist authorities insisted that candidates in Hong Kong's 2017 leadership election will have to be vetted by a loyalist committee.

Protesters say this will ensure the election of a pro-Beijing stooge, and their struggle has highlighted a litany of frustrations in the former British colony including a yawning income gap and lack of affordable housing.

Some in Admiralty expressed a sense of failure Thursday, after the authorities in Hong Kong and Beijing refused to give any concessions on political reform, but said the occupation had changed Hong Kong for good.

"I feel sad because we haven't achieved our mission, but I think there can be progress in the future," said 23-year-old welfare worker Dubi. "I think it's the start of something long-term."

Others were still determined to stand their ground.

"I'm not tired (of the campaign). I'll never be tired, only the government is tired," said 19-year-old student Alice.

There had been fears that radical splinter groups would dig in for a final stand, following violent clashes outside government headquarters in Admiralty at the end of last month.

But many said they did not want a confrontation and there were no clashes as police swept through.

Police said it would clear the last remaining protest site in Hong Kong's Causeway Bay at an "appropriate time".

"We hope to handle this as soon as possible," police assistant commissioner Cheung said, without offering details.