Deputy Prime Minister Chalerm Yubamrung has denied a claim made by a 15-year-old girl that she is his daughter.
Mr Chalerm said yesterday he is "700 million percent" certain he has never had a daughter.
Mr Chalerm, who has three sons, was responding to claims by Democrat MP Watchara Petchthong yesterday.
Mr Watchara told the media that a 15-year-old girl named Wayuhasthep Yubamrung visited parliament and had asked to see her "father," Mr Chalerm.
A Democrat staff member saw the woman, who brought along a 3-month-old baby, sitting at a bus stop after she was barred from entering parliament by officials.
The young woman asked the Democrat Party official to deliver a photo and a note to Mr Chalerm, whom she claimed was her father.
Mr Chalerm said he was exercising at home when he received a call. He was told a woman claiming to be his daughter was at parliament. "I told the caller I have three sons but no daughter," he said. "My last name, Yubamrung, is used by many people because it's an old one."
He has no plans to pursue the matter. He and his wife have known each other since secondary school, he said. "This is nothing serious," Mr Chalerm said.
Reporters called the number listed on the note but did not get through, as the phone had been turned off.
Searches of the girl's photo shown to the media by Mr Watchara turned up images of a Thai-Pakistani model, Amena Gul. Her image had been used to advertise cosmetic products.