Paetongtarn Shinawatra said on Tuesday her father Thaksin would stay at the Police General Hospital, not move to a private hospital, but she was worried about his heart condition.

Meanwhile, a political petitioner planned to ask the Ombudsman to check if Thaksin was really seriously sick and deserved to stay at the hospital and not in prison.

Ms Paetongtarn visited Thaksin at the Police Hospital again on Tuesday morning. Later, at Pheu Thai Party headquarters, she told reporters her father was exhausted but could still talk to her.

"I am worried about his heart. He also has a lung illness, but that is an old issue and should not cause any acute problem. I am more worried about his heart," Ms Paetongtarn said.

Thaksin had been tired and stressed since his return to Thailand, she said. The family learned at the same time as reporters that he had been transferred to Police General Hospital in the early morning of Aug 23.

Ms Paetongtarn confirmed that her father would remain at Police General Hospital and said there was no  plan to move him to a private hospital.

Asked how long Thaksin would remain at Police General Hospital, Ms Paetongtarn said she had asked doctors the same question but there was no answer yet because "there are many factors".

"In case of an emergency, it is necessary, because father is really elderly," she said.

Ms Paetongtarn said she was not bothered by allegations her 74-year-old father had received favoured treatment.

She denied he was in a VIP room at Police General Hospital. The view from the room was the Royal Thai Police Office, she said.

Asked about a possible request for a royal pardon, Ms Paetongtarn said her father would make that decision himself and the family would agree with it, regardless.

Political petitioner Srisuwan Janya said on Tuesday that he would ask the Ombudsman on Wednesday to verify if Thaksin was really seriously ill and deserved to stay at the Police General Hospital instead of in a prison hospital.