Veteran Beijing loyalist Rita Fan Hsu Lai-tai has urged Chief Executive Leung Chun-ying to call a press conference to clear doubts over the illegal structures at his home on The Peak.
The call puts more pressure on Leung to give an open account of the affair. On Friday he issued a 14-page statement explaining details and blaming a memory lapse for any confusion over the structures. But this only raised new questions.
Fan, who is running for another term as a Hong Kong deputy to the National People's Congress, said not everyone would accept a written explanation, but she dismissed calls for Leung to step down.
"No matter if it is a lapse of memory or whatever other reasons, he did not tell the truth in the first place," she said. "It is good for him to clarify the facts now. But if he could openly clear the doubts ... I think it could make more people believe he is honest and credible."
Leung won the chief executive election in March after taking advantage of rival Henry Tang Ying-yen's scandal over illegal structures at his Kowloon Tong home.
Fan refused to speculate whether Leung had "cheated on the central government".
Pan-democrat legislators said Leung's written statement was inadequate; others said he had proved he did not intend to lie.
Former chief secretary David Akers-Jones and Secretary for Food and Health Dr Ko Wing-man - both core Leung supporters - defended the chief executive's handling of the affair.
Akers-Jones said the public could clarify with Leung if they still had any doubts. "I haven't had time to read [Leung's statement] but giving his explanation like that, it's a very good thing," he said. "If the explanation isn't good enough, long enough, he will answer your questions."
Ko insisted there was no issue with Leung's integrity.
In his statement, Leung revealed that he had ordered the sealing up of a 200 sq ft laundry room - one of seven illegal structures in his house - four months before the election, after realising the room had been expanded by the previous owner.
Leung made no mention of the room while running for the top job. He also declined to comment on the matter openly for six months, citing a legal challenge to his election victory based on the illegal structures.
Vincent Ho Kui-yip, of the Hong Kong Institute of Surveyors, said Leung might have needed to apply to the Buildings Department before sealing up the room himself, if it involved a structural wall.
"It might help if he could explain to the public with more graphics and illustrations," he said.