PRO-DEMOCRACY protests in Hong Kong have escalated, a day after demonstrators upset over Beijing's decision to limit political reforms defied onslaughts of tear gas and appeals from the territory's top leader to go home.

Hong Kong's chief executive Leung Chun-ying reassured the public speculation the Chinese army might intervene was untrue.

Beijing-backed Mr Leung, who is deeply unpopular, said: "I hope the public will keep calm. Don't be misled by the rumours. Police will strive to maintain social order, including ensuring smooth traffic and ensuring the public safety."

Police tried to negotiate with protesters camped out on a normally busy road near government headquarters that was the scene of the tear gas-fuelled clashes that erupted on Sunday.

Protesters also occupied streets in other parts of Hong Kong Island, including the wealthy shopping area of Causeway Bay and the Wan Chai nightlife district as well as across the harbour in densely populated Mong Kok on the Kowloon peninsula.

Roads in those areas were closed.

More than 200 bus routes have been cancelled or diverted in a city dependent on public transport. Tube station exits have also been closed or blocked near protest areas.

The mass protest, which has gathered support from high school pupils to pensioners, is the strongest challenge yet to Beijing's decision to limit democratic reforms for the semi-autonomous city, formerly a British colony.

Authorities said some schools in areas near the main protest site would be closed.