Thailand's parliament elected political neophyte Paetongtarn Shinawatra as its youngest prime minister on Friday, only a day after she was thrust into the spotlight amid an unrelenting power struggle between the country's warring elites.

The 37-year-old daughter of divisive political heavyweight Thaksin Shinawatra sailed through a house vote and now faces a baptism of fire, just two days after ally Srettha Thavisin was dismissed as premier by a judiciary central to Thailand's two decades of intermittent turmoil.

At stake for Paetongtarn could be the legacy and political future of the billionaire Shinawatra family, whose once unstoppable populist juggernaut suffered its first election defeat in over two decades last year, and had to do a deal with its bitter enemies in the military to form a government.

Paetongtarn has never served in government and will become Thailand's second female prime minister and the third Shinawatra to take the top job after aunt Yingluck Shinawatra, and 75-year-old father Thaksin, the country's most influential and polarising politician.

Paetongtarn won with 319 votes, or nearly two-thirds of the house. She was not present in parliament and watched the vote from Pheu Thai's headquarters.

She will immediately face challenges on multiple fronts, with the economy floundering and the popularity of her Pheu Thai Party dwindling, having yet to deliver on its flagship cash handout programme worth 500 billion baht ($14.25 billion).

HOSTILE CLIMATE

The fall of Srettha after less than a year in office will be a stark reminder of the kind of hostility Paetongtarn could face, with Thailand trapped in a tumultuous cycle of coups and court rulings that have disbanded political parties and toppled multiple governments and prime ministers.

The Shinawatras and their business allies have borne the brunt of the crisis, which pits parties with mass appeal against a powerful nexus of conservatives, old money families and royalist generals with deep connections in key institutions.

Nine days ago, the same court that dismissed Srettha over a cabinet appointment also dissolved the anti-establishment Move Forward Party - the 2023 election winner - over a campaign to amend a law against insulting the crown, which it said risked undermining the constitutional monarchy. It has since formed a new opposition party.

The upheaval in the past few days also indicates a breakdown in a fragile truce struck between Thaksin and his rivals in the establishment and military old guard, which had enabled the tycoon's dramatic return from 15 years of self-exile in 2023 and ally Srettha to become premier the same day.

The decision to put Paetongtarn in play at such a critical juncture has surprised many analysts, who had expected Thaksin to delay his dynasty and avoid exposing Paetongtarn to the type of battles that led to the downfall of himself and sister Yingluck, who both fled overseas to avoid jail after their governments were ousted by the military.