Hong Kong leader Carrie Lam has been forced to suspend her annual address after being heckled in parliament.

Opposition lawmakers disrupted the Legislative Council session by shouting and projecting slogans behind her.

After a first interruption, the session resumed only to be interrupted again. It was then suspended - and Ms Lam delivered the address by video instead.

It means the extradition bill - the trigger for months of protests - could not be withdrawn formally.

The bill was suspended in July, but Wednesday's meeting was the first time the Legislative Council (Legco) had resumed since it was stormed by protesters in July, and was the first opportunity to withdraw the bill altogether.

But as Chief Executive Lam was about to begin her speech, opposition lawmakers began shouting and climbing on tables.

They also projected the words "Five demands - not one less" on the wall behind her. Since the protests began, they have widened from rallies against the bill to five key demands - including universal suffrage.

Opposition lawmaker Tanya Chan said Ms Lam was to blame for the Hong Kong's troubles.

"Both her hands are soaked with blood," she said. "We hope Carrie Lam withdraws and quits. She has no governance ability. She is not suitable to be chief executive."

It was the first time a Hong Kong chief executive had been unable to deliver a policy address in the chamber.

Pro-establishment lawmakers condemned the interruption of the session - saying the address was important for Hong Kong's economic future.

After the assembly was suspended, a pre-recorded speech was made available on the Legco website instead.

In the address, Ms Lam stressed her commitment to "one country, two systems" - the parallel political system introduced in Hong Kong after British rule ended - and said calls for Hong Kong independence would not be tolerated.

She announced several housing and infrastructure policies, saying housing was the most urgent issue the city faces.

The developments came just hours after Hong Kong protesters won a show of support from US lawmakers, who passed a bill aimed at upholding human rights in the city.