BANGKOK, Aug 29 ― The daughter of Thailand's jailed former premier Thaksin Shinawatra today said any move to seek a royal pardon for her father would be entirely "up to him” and such a process would take time.

In her first comments on the topic since her father's dramatic return last week from 15 years of self-exile, Paetongtarn Shinawatra said Thaksin, who must serve eight years for abuse of power and conflicts of interest, would be the one to pursue the matter himself.

"Drafting (a pardon request) takes time and it is up to him to choose the time and process,” Paetongtarn told reporters.

"He is doing it on his own, I have not seen it,” Paetongtarn said of a pardon, adding it was at his discretion.

Paetongtarn, a senior member of the Pheu Thai Party leading the incoming government, was speaking a day after visiting her father in hospital and said she concerned about his heart.

Thaksin, 74, was transferred from prison to a Bangkok police hospital last week just a few hours into his first night in jail, complaining of chest pains and high blood pressure.

His critics have dismissed his hospitalisation as a stunt and demanded poof of his illness.

"Doctors are monitoring everything,” Paetongtarn said, adding that he was stressed and fatigued.

The long-awaited return of Thaksin coincided with ally Srettha Thavisin being elected prime minister in a parliamentary vote that same day.

Srettha is in the process of forming a cabinet for the government led by Pheu Thai, the political vehicle of the Shinawatra family.

Speculation has been rife that the influential Thaksin had brokered a deal with his enemies in the military and royalist establishment to allow his return and possibly, early release. He has denied that.

An anti-Thaksin group has lodged a complaint at the corrections department seeking to block Thaksin from seeking a royal pardon, arguing corruption cases should not be entitled to clemency. ― Reuters