Almost two million people have filled the streets of Hong Kong to lead an unprecedented wave of protests against the city’s embattled leader Carrie Lam, after she failed to withdraw the contentious extradition bill completely.

Hours after the demonstrations started, the Hong Kong chief executive issued a rare apology and reassured the public that it did not have a timetable to restart discussions on the bill which would allow for extraditions to China.

“The chief executive acknowledged that the lack of government work has caused great contradictions and disputes in the community of Hong Kong,” the government said in a statement on Monday (Australian time).

“Many members of the public are disappointed and saddened. The chief executive apologises to the public and promises to accept it with the utmost sincerity and humility,” the statement added.

Ms Lam earlier promised to indefinitely suspend efforts to pass the bill in the face of public pressure. However, opponents reportedly warned they saw it as a way to buy time to intimidate or demoralise opponents of the bill and called for her resignation.

A large group of demonstrators next to the police headquarters could be heard belting out a song from musical Les Misérables called “Do You Hear The People Sing?”

A large group of protesters was singing “Do you hear the people sing?” Sunday afternoon in Hong Kong. Tens of thousands of defiant citizens took to the streets calling for CE Carrie Lam to fully withdraw the controversial extradition bill. Video from CNN's @danqtham pic.twitter.com/r71YQc2R01

— Stella Ko (@ko_stelly) June 16, 2019

The Civil Human Rights Front (CHRF), which organised the march, said demonstrations will continue until the bill was cancelled.

“Should the government refuse to respond, only more Hong Kongers will strike tomorrow,” CHRF said.

The conflict, which slipped into unusually violent clashes with police last week, is one of the toughest tests of the territory’s special status since China took control in a 1997 handover.

The demonstrators carried banners demanding that Ms Lam step down and repeatedly broke into chants.

Carrie Lam speaks during a news conference the day before the protests. Photo: Getty

Walking slowly and shouting “withdraw” and “resign”, the crowd filled a wide thoroughfare and side streets paralleling the waterfront of Victoria Harbour as tourists and shoppers who drive much of the Asian financial hub’s economy looked on.

Opponents worry the law could be used to send criminal suspects to China to potentially face vague political charges, possible torture and unfair trials.

“Our demands are simple. Carrie Lam must leave office, the extradition law must be withdrawn and the police must apologise for using extreme violence against their own people,” bank worker John Chow said as he marched with a group of his friends.

Protesters focused their anger on Ms Lam, even while acknowledging that she had little choice but to carry through dictates issued by Beijing, where President Xi Jinping has enforced increasingly authoritarian rule.

Many believe Hong Kong’s legal autonomy has been significantly diminished despite Beijing’s insistence that it is still honouring its promise, dubbed “one country, two systems,” that the territory can retain its own social, legal and political system for 50 years after the handover.

-with AAP