Police remove a tent as they attempt to clear a demonstration site near the chief executive's office in Hong Kong on Dec 1, 2014. EDMOND TANG / CHINA DAILY

HONG KONG - Hong Kong's High Court has ordered the main protest sites that have choked the financial city for months to be cleared from Thursday, building up to a final showdown between protestors and Hong Kong authorities.

A local bus company, which was granted an injunction against street blockades at the site in Admiralty, home to government offices and next to the main Central business district, has received an official clearance order from the High Court, according to notices posted in local papers on Tuesday.

Splinter protest groups are springing up and fast-tracking action plans as student-led demonstrators consider a retreat from the main protest site which has blocked key downtown arteries since the end of September.

Police are expected to clear the sites on Thursday with over 3,000 officers, the South China Morning Post newspaper reported, citing police sources.

At their peak, the Hong Kong rallies drew more than 100,000 on to the streets, but numbers have since dwindled and public support for the movement has waned.

Clashes between protesters and police increased at the end of November after the clearance of protest sites in the densely populated working-class district of Mong Kok district, on the Kowloon side of Hong Kong harbour.

One man was jailed for six months on Monday for threatening to burn Mong Kok demonstrators with paint thinner, media said on Monday.