Demonstrators have clashed with police firing rubber bullets, tear gas and water cannons in Hong Kong, as politicians postponed the reading of a controversial extradition bill.

Tens of thousands of protesters took to the streets on Wednesday morning, knocking down barriers and tussling with police outside the offices of the Legislative Council where the proposed law was due to be debated at 11am, four days after they staged what was believed to be the largest protest march since Hong Kong was handed over to China from Britain in 1997.

In what appeared to be a rare victory for protesters, a government statement said the debate on the bill would be "changed to a later time" yet to be decided. Officials called on demonstrators to stop blocking streets and "disperse as soon as possible".

But as the protests continued, the mostly young people involved said they would not placated by the unspecified delay to the bill. "We won't leave till they scrap the law," said one young man wearing a black mask and gloves. "Carrie Lam has underestimated us. We won't let her get away with this."

The extradition bill, which is backed by Beijing, would allow criminal suspects in Hong Kong to be sent for trial in mainland China. Critics say it would open up Hong Kong's political dissidents to show trials on the mainland, where standards of judicial independence and fair process are far weaker than in the semi-autonomous territory.

Hong Kong: Extradition law protests continue into second week Show all 40 1 /40 Hong Kong: Extradition law protests continue into second week Hong Kong: Extradition law protests continue into second week A reported two million people took to the streets to protest against a controversial extradition law in Hong Kong on June 16 AFP/Getty Hong Kong: Extradition law protests continue into second week Protesters part to allow an ambulance to pass through during a protest on June 16 that reportedly attracted two million people AFP/Getty Hong Kong: Extradition law protests continue into second week A protester pays tribute to a man who died after falling from a scaffolding during the protests against against the extradition law proposal on June 17 Reuters Hong Kong: Extradition law protests continue into second week Following the demonstration, protesters cleared rubbish from the roads where a reported two million people had marched AP Hong Kong: Extradition law protests continue into second week Protesters part to allow buses to pass through during a protest on June 16 that reportedly attracted two million people Getty Hong Kong: Extradition law protests continue into second week A riot police officer strikes at protesters during a protest against the extradition law proposal outside the Legislative Council of Hong Kong on June 12 Reuters Hong Kong: Extradition law protests continue into second week A police officer fires tear gas at protesters during a protest against the extradition law proposal outside the Legislative Council of Hong Kong on June 12 Reuters Hong Kong: Extradition law protests continue into second week Protesters scatter as police fire tear gas during a protest against the extradition law proposal outside the Legislative Council of Hong Kong on June 12 Pauline Leung via Reuters Hong Kong: Extradition law protests continue into second week Protesters carry a banner opposing the extradition law proposal outside the Legislative Council of Hong Kong on June 16 AP Hong Kong: Extradition law protests continue into second week A protester holds a picture of an injured man who later died after falling from a scaffolding during the protests against against the extradition law proposal on June 17 Reuters Hong Kong: Extradition law protests continue into second week Protesters run after police fire tear gas during a protest against the extradition law proposal outside the Legislative Council of Hong Kong on June 12 AFP/Getty Hong Kong: Extradition law protests continue into second week A protester rests after facing water cannons fired by police during a protest against the extradition law proposal outside the Legislative Council of Hong Kong on June 12 Reuters Hong Kong: Extradition law protests continue into second week Police officers use a water canon on a lone protestor near the Legislative Council in Hong Kong on June 12 AFP/Getty Hong Kong: Extradition law protests continue into second week Protesters gather outside the Legislative Council in Hong Kong on June 12 AP Hong Kong: Extradition law protests continue into second week A protester waves a British flag outside the Legislative Council in Hong Kong on June 12 Getty Images Hong Kong: Extradition law protests continue into second week Protesters leap over barricades as they occupy roads by the Legislative Council in Hong Kong on June 12 AFP/Getty Hong Kong: Extradition law protests continue into second week Some protesters run after police fire tear gas during a protest against the extradition law proposal outside the Legislative Council of Hong Kong on June 12 AFP/Getty Hong Kong: Extradition law protests continue into second week Police officers use pepper spray against protesters during clashes after a rally against the extradition law proposal on June 10 AP Hong Kong: Extradition law protests continue into second week A protester sits down in front of riot police during a protest against the extradition law proposal on June 12 Reuters Hong Kong: Extradition law protests continue into second week Protesters sit in a demonstration following violence in the previous day of protests on June 13 Reuters Hong Kong: Extradition law protests continue into second week Protesters barricade themselves in an area outside the Hong Kong Legislative Council during clashes with police after a rally against the extradition law proposal in Hong Kong on June 10 AFP/Getty Hong Kong: Extradition law protests continue into second week A bloody-faced police officer is led away by a colleague after clashing with protesters in a rally against the extradition law proposal on June 10 AP Hong Kong: Extradition law protests continue into second week Protesters march through Hong Kong in opposition to the extradition law proposal on June 9 AFP/Getty Hong Kong: Extradition law protests continue into second week A protester sits in front of a riot police line during clashes between protesters and police following a protest in Hong Kong in opposition to the extradition law proposal on June 10 AFP/Getty Hong Kong: Extradition law protests continue into second week Protesters march through Hong Kong in opposition to the extradition law proposal on June 9 EPA Hong Kong: Extradition law protests continue into second week A protester lifts a barricade while a police officer charges in with his baton during clashes after a rally against the extradition law proposal in Hong Kong AFP/Getty Hong Kong: Extradition law protests continue into second week A protester is arrested during a clash after a rally against the extradition law proposal in Hong Kong on June 10 Getty Hong Kong: Extradition law protests continue into second week Protesters hold pictures of Hong Kong Chief Executive Carrie Lam during a rally against the extradition law proposal in Hong Kong on June 9 AP Hong Kong: Extradition law protests continue into second week A protester wave a Union Flag in front of police officers during a protest against the extradition law proposal in Hong Kong on June 10 Reuters Hong Kong: Extradition law protests continue into second week Protesters gather outside the Hong Kong Legislative Council during a rally against the extradition law proposal in Hong Kong on June 10 AFP/Getty Hong Kong: Extradition law protests continue into second week A protester is grabbed by a policeman as he crosses the police line during a rally against the extradition law proposal in Hong Kong on June 10 AP Hong Kong: Extradition law protests continue into second week Protesters gather outside the Hong Kong Legislative Council during a rally against the extradition law proposal in Hong Kong on June 10 AFP/Getty Hong Kong: Extradition law protests continue into second week A police officer detains a demonstrator during a protest to demand authorities scrap a proposed extradition bill with China, in Hong Kong, China June 9, 2019. REUTERS/Thomas Peter Reuters Hong Kong: Extradition law protests continue into second week Police officers detain a demonstrator during a protest during a rally against the extradition law proposal in Hong Kong on June 10 AP Hong Kong: Extradition law protests continue into second week A protester shouts next to police officers during a protest during a rally against the extradition law proposal in Hong Kong on June 10 AP Hong Kong: Extradition law protests continue into second week Protesters march through Hong Kong in opposition to the extradition law proposal on June 9 AP Hong Kong: Extradition law protests continue into second week Police officers detain a demonstrator during a protest during a rally against the extradition law proposal in Hong Kong on June 10 Reuters Hong Kong: Extradition law protests continue into second week Police officers detain a demonstrator during a protest during a rally against the extradition law proposal in Hong Kong on June 10 Reuters Hong Kong: Extradition law protests continue into second week Protesters gather in a park in Hong Kong opposition to the extradition law proposal on June 9 Reuters Hong Kong: Extradition law protests continue into second week A protester sits by ramshackle barriers after clashes between protesters and police following a protest in Hong Kong in opposition to the extradition law proposal on June 10 AP

And the bill is seen as just the latest measure signalling greater Chinese control and the erosion of civil liberties in Hong Kong. China has been accused of interfering with Hong Kong elections, blocking democratic reforms and rights violations that include the abduction of five booksellers who specialised in works critical of Chinese leaders.

The extradition bill protests represent Hong Kong's biggest political crisis since pro-democracy demonstrations closed down parts of the city centre for more than three months in 2014.

They pose a challenge to China's ruling Communist Party and President Xi Jinping, who has in the past said he would not tolerate Hong Kong being used as a base to challenge the party's authority. But they are also young Hong Kongers alienated by a political process dominated by the territory's economic elite a chance to vent their displeasure.

Government staff were advised not to go to into work and those already on the premises were told to "stay at their working place until further notice".

Protesters said they hope the blockade will persuade chief executive Carrie Lam's administration to shelve the proposed amendments to the Fugitive Offenders Ordinance and the Mutual Legal Assistance in Criminal Matters Ordinance.

One protester, who gave only his first name Marco, said: "We want the government to just set the legislation aside and not bring it back."

A fellow protester, who gave her name as King, said the protest was a watershed moment for Hong Kong's young generation, who face difficult job prospects and skyrocketing housing prices.

"We have to stand up for our rights or they will be taken away," she said.