The Democratic Party has called on voters to ignore a "malicious" appeal to cast blank ballots in Sunday's election for the Legislative Council "super seats".
The radical People Power group, which is not taking part in the election, has been campaigning for supporters to cast blank ballots as a protest vote.
The five seats, in a functional constituency for district councils, were created under 2010 electoral forms which People Power argues only served to stall Hong Kong's progress towards full democracy. Some 3.2 million voters - all those without a vote in any other functional constituency - will be eligible to cast ballots for the seats, giving the winners a bigger mandate than colleagues.
Democratic Party chairman Albert Ho Chun-yan, who heads one of five slates of candidates vying for the seats - two individuals are also standing - urged people to vote for the pan-democratic camp to show their support for democracy.
"Those who came up with the so-called idea of casting blank ballots are exceptionally malicious," Ho said.
Three of the five slates are led by pan-democrats: Ho, his Democratic Party colleague James To Kun-sun, and Frederick Fung Kin-kee of the Association for Democracy and People's Livelihood.
Two other lists are led by Beijing loyalists - Starry Lee Wai-king of the Democratic Alliance for the Betterment and Progress of Hong Kong and Chan Yuen-han of the Federation of Trade Unions - while the DAB's Lau Kong-wah is also standing. The other candidate is independent Pamela Peck Wan-kam.
Both camps are expected to win two seats each, leaving a fierce fight for the fifth seat. To burst into tears yesterday at the prospect that some of his supporters would instead vote for Fung, who is more popular popular than To according to a rolling opinion poll.
Lee sidestepped questions about talk that the DAB might sacrifice one Hong Kong Island seat to the FTU in return for the FTU's support for her in the super-seat contest.
"The DAB will try to get all its candidates to win Legislative Council seats in accordance with its deployment," she said.
With the rolling poll showing Lee trailing, there are suggestions the FTU will divert some votes to her. "I think it would be very difficult to persuade Chan to do it," Lee said.