“We have decided to nominate Paetongtarn Shinawatra,” party secretary Sorawong Thienthong said at a press conference in Bangkok.
On Friday, lawmakers in Parliament – where the Pheu Thai party leads a ruling coalition – will vote on whether to confirm Paetongtarn as prime minister.
The vote came after Thailand’s Constitutional Court dismissed Prime Minister Srettha Thavisin on Wednesday, ruling that he had violated regulations by appointing a cabinet minister with a criminal record.
Srettha was the third Pheu Thai Party prime minister to be removed from office by the Constitutional Court and leaves office after less than a year.
Thai politics has endured two decades of chronic instability marked by coup attempts, street protests and court rulings.
Much of this development has been fuelled by the long-running struggle of the military and royalist establishment against progressive parties with links to Thaksin.