Thailand's King Maha Vajiralongkorn has sworn in Prime Minister Paetongtarn Shinawatra and 35 cabinet ministers in Bangkok, ushering in a new government in Southeast Asia's second-largest economy after a period of political turmoil.

Paetongtarn, 38, leader of the ruling Pheu Thai party, was elected by parliament last month to become Thailand's youngest prime minister after her predecessor Srettha Thavisin was dismissed by a court order over an ethics violation.

The cabinet, which was formally endorsed by the king on Wednesday, comprises 17 members from Pheu Thai, including the premier, and another 19 positions divided among coalition partners.

Dressed in official uniform, Paetongtarn and her cabinet ministers swore their allegiance in front of King Vajiralongkorn and Queen Suthida in a ceremony at Bangkok's Dusit Palace.

"I want to wish, with gladness, that the cabinet will have the encouragement and determination to perform your duties as you have sworn for the benefit of the country and people," the king said on Fridauy after the cabinet's oath of allegiance.

Second woman holding highest position

Paetongtarn and the cabinet ministers bowed after the king's remark.

The youngest daughter of the divisive former premier Thaksin Shinawatra, Paetongtarn has not served in government previously and will face challenges on multiple fronts, including a floundering economy.

She is also the second woman and fourth member of the Shinawatra clan to hold Thailand's top elected position, with three previous premiers removed by coups or court decisions.

Paetongtarn's government will deliver its policy statement to parliament next Thursday and Friday, marking the formal start of her administration.