Protesters in Hong Kong tried to smash their way into a government building as thousands took to the streets to mark the 22nd anniversary of its return to China.

People rammed the safety glass protecting those inside using a cargo cart and poles, paying little attention to police signs urging them to stop charging.

Officers eventually managed to commandeer the cart, and riot shields and pepper spray were also used to push back hundreds of demonstrators who had blocked a nearby street.

The disruption forced Hong Kong leaders and guests to watch the annual commemorations from inside a convention centre, rather than outside as they would usually.

While the flag-raising ceremony and other celebrations always draw protests, the demonstration this year has been much larger than usual because of widespread opposition to an extradition bill that would have allowed suspects to be extradited to the mainland to face trial.

The mass march on Monday was the third demonstration in three weeks after the bill awakened broader fears that China is eroding Hong Kong's freedoms.

Protesters try to break the glass walls of the Legislative Council in Hong Kong | Image: Vincent Yu/AP/Press Association Images

It forced a u-turn from the embattled leader of Hong Kong, Carrie Lam, who has pledged to be more responsive to public sentiment after coming under incessant criticism for trying to push through the legislation.

She said the protests and marches, which have attracted hundreds of thousands of students and other participants, have taught her that she needs to listen better to the youth and people in general.

In a speech at the convention centre, she said: "This has made me fully realise that I, as a politician, have to remind myself all the time of the need to grasp public sentiments accurately."

She added: "I will learn the lesson and ensure that the government's future work will be closer and more responsive to the aspirations, sentiments and opinions of the community."

Demonstrators wave Chinese and Hong Kong flags and shout slogan during a rally in support of the police | Image: SOPA Images/SIPA USA/PA Images

On Sunday, more than 50,000 people rallied in support of Hong Kong police, who have been criticised for using tear gas and rubber bullets during clashes with demonstrators that left dozens injured on June 12th.

More than one million people took to the streets in two previous marches in June, organisers estimate.

The Hong Kong government has already postponed debate on the extradition bill indefinitely, but protest leaders want the legislation formally withdrawn and the resignation of chief executive Carrie Lam.

They also are demanding an independent inquiry into police actions on June 12th.