Hong Kong lawmakers were set Thursday to adopt a political reform plan that will give voters a greater say in the Chinese financial hub's running but stops well short of full democracy.

Pro-democracy lawmakers failed to postpone the vote after a day-long debate on Wednesday that attracted raucous crowds of rival activists, both supporting universal suffrage and backing communist Beijing's stewardship of Hong Kong.

Scores of police officers, bracing for any possible clashes between the rival camps, maintained a heavy presence outside the Legislative Council building under heavy rain.

Moderate democratic legislators who have declared their support for the plan, ensuring its eventual passage later Thursday, had to be escorted out by police late Wednesday as demonstrators screamed "shameful!" at them.

"We are disappointed that many lawmakers have decided to give up their dreams for democracy after years of campaigning," Chan King-fai, a leader of the Post 80s, a group of activists in their 20s and 30s, told AFP.

"They think there is no point to take to the streets any more. That's precisely why we are here - to remind Hong Kong that people's power is still important if we want to make changes," he said.

But the Democratic Party, Hong Kong's oldest opposition group, says the plan is still an important advance even if it only envisages a modest expansion to the electoral base for the city's leader and legislature.

Hong Kong, which was handed over by Britain in 1997, has a legal and administrative system independent from mainland China but its constitutional development falls under Beijing's control.

While the financial and trading citadel in southern China has some direct democracy, power ultimately rests in the hands of a Beijing-backed chief executive and business elites.

In a U-turn on Monday, the government said all 10 new seats that it proposes to add to the Legislative Council would be directly elected, a concession that won over the Democratic Party.

Only half the current 60-seat legislature is directly elected, with the rest picked by "functional constituencies" based on professions and mainly comprising pro-Beijing elites.

Previously, the government had proposed to split its planned 10 new seats between directly elected and functional constituencies.

The city's leader is chosen by an election committee made up of 800 members handpicked by Beijing. The government is proposing to increase the number of committee members to 1,200.

Pro-democracy lawmakers argued that more time was needed to consider the plan, following the last-minute changes introduced by the government on Monday. But the request was blocked Wednesday.

Beijing has said that, at the earliest, universal suffrage can be introduced for the election of Hong Kong's chief executive in 2017 and for the legislature in 2020.

That would augment freewheeling Hong Kong's status as a constitutional curiosity within China, which as a whole is controlled with an iron fist by the communist party.

- AFP