Leading pan-democrats remain split on whether they should pass the government's electoral reforms for 2012 even if Beijing makes concessions.
Democratic Party veteran Martin Lee Chu-ming said he would vote against the proposals whether or not they were amended, as his party has suggested, to allow everyone a vote on five new seats proposed for the Legislative Council's district councils functional constituency.
Lee said the measure could pave the way for the retention of functional constituencies when universal suffrage was introduced for the Legco election in 2020.
The Democratic Party will discuss the issue at a seminar today ahead of a vote on Monday.
'I will not support this proposal, although it would improve the democratic elements in Legco for the short term,' he said. 'I will vote against it in the party meeting on Monday, but I know many others are thinking of supporting it.'
Civic Party leader Audrey Eu Yuet-mee also said she was inclined to vote against the proposal. Her party will also make a decision on Monday.
Democratic Party chairman Albert Ho Chun-yan said on Tuesday that he would resign if the party decided to vote against the proposals even if they included the suggested change.
But the former leader of the city's Catholic diocese, Cardinal Joseph Zen Ze-kiun, an advocate of greater democracy, said: 'The Democrats' proposal could become a breakthrough. If these five seats, barring any tricks in their nominations, can be returned by people in Hong Kong, that will be one person, two votes. It is a de facto change in the nature of functional constituencies.'
Zen, who earlier called on pan-democrats to unite against the government's proposals if there was no concession, said the Democrats' idea was worth considering if it was taken as a first step and the fight for universal suffrage continued.
But he warned that pan-democrats must reach a consensus quickly and clarify how this proposal met their demands for the ultimate abolition of functional constituencies. If they remained split on the election it could damage the camp's unity.
Lee predicted the government would introduce a nominations threshold for the new seats that would ensure the pan-democrats could gain no more than two.
He said they were also unlikely to win more than two of the five proposed new seats in Legco geographical constituencies.
But the real danger, he said, was that Beijing could claim that, since Hongkongers had already got a taste for voting in functional constituencies, which opened the way for elements of direct election to be introduced in these trade-based seats, they could be kept beyond 2020.
Eu, fresh from her victory over Chief Executive Donald Tsang Yam-kuen in Thursday's televised debate, said her personal inclination was not to support the Democrats' proposal.
In a speech at the Foreign Correspondents' Club, Eu said including the Democrats' proposal for the functional constituency seats in the government package on which Legco would vote on Wednesday 'would not be respectful to the people of Hong Kong' since the government had consulted the people on a different package.
She said the recent backing for the Democrats' proposal from pro-business functional constituency lawmakers would give the government an excuse to say it had resolved the question of what constitutes universal and equal suffrage 'and the question of a road map to universal suffrage will be put aside again for another five years'.