Authorities on Tuesday cleared part of Hong Kong's main pro-democracy protest camp, facing no resistance as they launched the first of several planned evictions to reopen roads blocked for nearly two months.

Demonstrators have been camped on three major thoroughfares since September 28 demanding free leadership elections for the semi-autonomous Chinese city, but public support has ebbed as the weeks pass with little progress.

The Chinese government insists that candidates for the 2017 vote must be vetted by a loyalist committee -- an arrangement the protesters say will ensure the election of a pro-Beijing stooge.

Dozens of police and bailiffs stood guard Tuesday as workers dismantled metal barricades blocking access to a skyscraper opposite government headquarters, on the edge of the sprawling main camp in the central Admiralty district.

The operation, which took place under the watch of a gaggle of protesters and a huge scrum of journalists, came after the owners of the CITIC Tower office block won a court injunction ordering that protesters clear its immediate vicinity.

Tensions rose briefly as bailiffs removed further barricades from a roundabout opposite government headquarters, with protesters angrily shouting that the area was not covered by the court ruling.

Pro-democracy lawmaker Lee Cheuk-yan accused the authorities of "hiding behind the courts" in a bid to end the protests, rather than pursuing talks with the activists.

"What is needed is a political solution. We want the government to negotiate -- not police action," Lee told reporters.

"The protesters have been very restrained already by giving up part of the space. We expect the same from the other side."

- Public support fades -

The injunction only covers the area around the gleaming CITIC Tower, leaving a long section of a multi-lane highway still under occupation and filled with hundreds of colourful tents.

Protesters said they had no intention of budging from the rest of the camp.

"I will not stop them (removing these barricades). The movement doesn't necessarily need to take place here," said 25-year-old Max Cheng as he stood watching with around a dozen other protesters.

He added: "If the government doesn't respond to the people's demands, it will ultimately have to face the consequences."

Bus companies and taxi drivers' groups are pursuing three similar court orders to clear other blocked roads in the city, saying their business has taken a heavy hit from weeks of traffic disruption.

One of two injunctions seeking the clearance of roads in the Mongkok district of Kowloon, home to the second-largest protest camp, was published on Tuesday -- suggesting a similar operation there could be imminent.

Court proceedings are continuing over other parts of the main camp at Admiralty. The third protest site is in the busy shopping district of Causeway Bay.

Protesters had already mostly cleared the area outside CITIC Tower in anticipation of Tuesday's swoop by authorities.

In a statement late Monday, police had pledged "resolute action" against anyone obstructing the bailiffs clearing the area around the skyscraper, saying they could face charges of criminal contempt of court.

The protests drew tens of thousands at times initially, but the crowds have shrunk dramatically as the movement struggles to keep up momentum.

Surveys suggest that public opinion is starting to turn against the campaign.

A poll by Hong Kong's Chinese University conducted on November 5-11 found more people opposed the Occupy movement than supported it -- the first time this has been the case since the university started the poll in September.

About 67 per cent of respondents said the protesters should go home, the survey said.

Hong Kong's leader Leung Chun-ying said it was "abundantly clear by now that the occupiers are and have been breaching the law of Hong Kong".

"Hong Kong is a law-abiding society and the rest of Hong Kong expect the occupiers, like everyone else in Hong Kong, to follow the law," he said in a statement.