If the proposal is voted down, the city's chief executive will be continue to elected by the existing election committee.
Pan-democratic lawmakers will resume their efforts to broker a deal with the central government for free and fair elections – with a fresh round of protests on the cards.
"I think the democrats will continue to protest and engage in various forms of activity to educate the community," Michael Davis, Professor of Law at the University of Hong Kong. "I would hope the central government and Hong Kong government would learn a lesson from it and reexamine their position," he said.
In the unlikely event that the proposal is passed, this would raise the specter of another episode of political unrest in the city.
"If their attempts to stop the reform proposal have failed, they will be very vociferous in protesting against it," said David Akers-Jones, president at the Business and Professionals Federation of Hong Kong.