Hong Kong's legislature was plunged into chaos on Monday after a pro-Beijing lawmaker was elected chair of a key committee.

There were scuffles after Starry Lee became head of the House Committee, which vets bills and decides when to present them for a final vote.

Her election will likely speed up the passing of a controversial bill that would criminalise abuse of the Chinese national anthem.

At Monday's meeting, pro-democracy lawmakers held up placards that read "Abuse of Power" and "CCP tramples HK legislature," referring to China's ruling Communist Party.

Within minutes, at least five lawmakers were ejected for disorderly behaviour, with at least one lying injured on the ground as the meeting was briefly suspended.