Henry Tang denies having had an extramarital affair with Esther Lam, saying they are just friends.
"I admit that I have known Ms Lam since we met at a social gathering," Tang said yesterday. "We are simply ordinary friends."
He expects more allegations to surface, saying Lam will not be the last name the media will dredge up.
Tang made his remarks hours after Heung Yee Kuk vice chairman Daniel Lam Wai-keung denounced media reports that his daughter - who is married with a son - carried on a two- year affair with the troubled chief executive hopeful after they met at a dinner reception in 2009.
Lam accused the media of jumping to conclusions after seeing a January 2010 photo of Tang with an arm around Esther.
"The photo was taken during a gathering in which a large number of people joined," he said.
"Hong Kong is an open international city. My daughter grew up and studied overseas. Unlike countries like Iraq and Iran, where women may be killed for lifting the veil, it is not unusual for both of them to have chatted and had pictures taken in a normal social gathering."
Lam stressed his daughter has never gone out on a date with Tang.
Tang has declined to comment on media reports concerning several "love e-mails" purportedly sent to Esther two years ago.