Beijing-friendly heavyweight and Legislative Council president Tsang Yok-sing is considering whether to step into the chief executive race.
The prospect of such a high-profile new contender heightens the uncertainty surrounding the contest for the top job as embattled hopeful Henry Tang Ying-yen insists on continuing with his bid.
Tsang said yesterday he was 'seriously considering' a run after what he called 'a dramatic turn in the chief executive election'.
It came a day after New People's Party chairwoman Regina Ip Lau Suk-yee declared her interest in rejoining the fray.
Tsang, 64, was apparently referring to the escalating scandal over former chief secretary Tang's illegal home structures. The affair has raised questions about his integrity, prompted accusations he was shifting the blame to his wife and heaped pressure on Tang to withdraw.
The founding chairman of the Democratic Alliance for Betterment of Hong Kong, Tsang had earlier ruled himself out of the running. Yesterday he said: 'In view of the changes in the chief executive election in the past few days and the opinions and worries expressed by many of my friends [since Thursday], I promised these enthusiastic friends that I would seriously consider it.'
He said his main consideration was whether he was capable of leading the city.
He would also have to resign as Legco president should he stand for the race, he added.
But he is not required to quit the Democratic Alliance for the Betterment and Progress of Hong Kong until he is elected as the chief executive. He did not clearly say if he was or had been a Chinese Communist Party member.
Tam Yiu-chung, chairman of the DAB, which holds 147 seats in the 1,200-strong Election Committee, said: 'If he opts to run, I will respect his decision and consider how to help him.'
Since Tsang has still to make up his mind, Tam said there was no need yet to ask party members to suspend nominations of candidates like Tang and Leung Chun-ying.
A source close to Beijing said Tsang's move was aimed at thwarting some 'political careerists' from entering the race.
Beijing also wants to send out the message to Election Committee members that both Tang and Leung were still acceptable to it, the source said.
Ip said that in the past two days, some committee members had encouraged her to contest the March 25 race. She vowed to try her best to secure enough nominations.
Tang said yesterday that so far, no Election Committee members had withdrawn their nominations and he 'insists on running'.
His election office's senior adviser, former chief executive of the Monetary Authority Joseph Yam Chi-kwong, also said he would continue to back Tang although Tang 'didn't do very well in handling the illegal structure issue'.
Federation of Trade Unions lawmaker Wong Kwok-kin said he personally would not nominate or vote for Tang.
More committee members, including insurance-sector lawmaker Chan Kin-por - who has already signed to nominate Tang - said they were considering whether to withdraw their support for him.