More than 10,000 people took to the streets of Hong Kong yesterday to protest against Beijing's ruling that it alone will determine the shape and timing of elections in the city.

In a move sure to irk China, the protesters marched to Beijing's representative office in Hong Kong chanting "Return the power to the people" and "One man, One vote".

The protesters, including women, children and people in wheelchairs, punched their fists in the air and waved banners that read "One country, two systems fail completely" and "Return the power to the people". They also carried balloons with a caricature of Hong Kong chief executive Tung Chee-hwa.

"The reason why I'm doing this is for the future of my child, for her freedom," said housewife Bonnie Cheung, who brought her young daughter to the protest.

It was the first mass protest organised after China's parliament revised clauses in Hong Kong's constitution last week, giving Beijing full control over how and when the city chooses its leaders and lawmakers.

"It's an attack on Hong Kong's legal system and its autonomy," Martin Lee, one of the city's leading democracy lawmakers, said of Bejing's ruling.

Organisers said about 20,000 people had joined the march. Police said they would not provide a number. The marchers dispersed peacefully after tying black ribbons to the gate of Beijing's liaison office to symbolise their anger.

The protest also drew hecklers. "All of you disgusting people, you should all be shot," one man shouted at the marchers.

Hong Kong's government said in a statement it had noted the concerns of the people over China's interpretation of the city's constitution.

Last July, about 500,000 people took to the streets of Hong Kong over Beijing's demand for an anti-subversion law. The protest, which forced the planned law to be shelved, shocked the Chinese leadership and triggered a campaign by Beijing to discredit the city's pro-democracy figures.

While the move to change the constitution is legal, it has provoked an outcry from people, who say it erodes the high degree of autonomy China promised Hong Kong when it took back the British colony in 1997.

Angry with the local Beijing-backed government, many Hong Kong people have been agitating for full direct elections from as soon as 2007, a possibility allowed under the Basic Law. But the review means this prospect is now more remote than ever.

Beijing, which already has the power to veto any political reform, now has the added power to decide if changes are even needed, meaning it can delay any change for as long as it likes.

Observers see China's tactics so far as aimed at dousing democratic aspirations ahead of the city's legislative council elections in September. China fears full democracy would yield a leader in the city who can challenge the authority of the central leadership. The communist government also fears full democracy in Hong Kong could spread to the mainland, undermining its ability to govern the world's most populous nation. It is also afraid that democratic aspirations would fester and grow into demands for independence for Hong Kong, giving Beijing the same sort of headache it faces in Taiwan, one of Asia's freest democracies.

China views self-governing Taiwan as a renegade province that must be reunited, by force if necessary.