Beijing: Hong Kong's political crisis shifted from its city streets to an austere university lecture theatre as student protest leaders faced off with government officials in a much-anticipated televised debate after more than three weeks of an unprecedented civil disobedience campaign.

Across the city, a strong police presence looked on as thousands of protesters gathered at protest sites on Tuesday evening; enthralled at the contest beamed live on to big screens set up at the venues from outside government headquarters in Admiralty, to the gritty Kowloon district of Mong Kok.

Enthralled: Tens of thousands of protesters gather to listen to the talks at the main protest site in Hong Kong. Credit:Getty Images

That the talks were convened was testament to the impact the protests have had, something that Carrie Lam, Hong Kong's chief secretary and the most senior official on the government's panel, conceded.

"We cannot deny that in the past month, the class boycott started by you and the occupation movement, something huge has happened," Ms Lam said during the debate. "Such a social movement is large-scale and its impact is far-reaching."