Former Legislative Council president Rita Fan Hsu Lai-tai backed out of standing in the chief executive election following six months of consideration.
'I have little confidence that I could handle the heavy burden of being chief executive till 2017,' the Beijing loyalist, 66, said on Sunday.
Fan, a member of the Standing Committee of the National People's Congress, denied repeatedly that the central government had put pressure on her not to join the race.
'This is purely a personal decision. Beijing has never dissuaded me,' she said.
In an opinion poll commissioned by the South China Morning Post last month, Fan lagged behind former Executive Council convenor Leung Chun-ying by 10 percentage points.
Fan admitted that she paid the price of a drop in popularity for being indecisive about her intention to run.
Two undeclared front runners, Leung and former chief secretary Henry Tang Ying-yen, said they respected Fan's decision.
Veteran commentator Lau Yui-siu said the circumstances surrounding the race were clearer, now that Fan had opted out.
'Age is a feeble excuse for not contesting the top job,' Lau says. 'I think Fan is waiting for a signal from the central government.'
New People's Party chairwoman Regina Ip Lau Suk-yee said she had more confidence in securing a nomination from the election committee because she shared a similar background to Fan. Ip's party will meet today to discuss support for her candidacy.