Thai politics were in chaos on Wednesday as the ruling Pheu Thai party said it had sought royal approval to dissolve the parliament for a new election, moments after the biggest group in the house said it would back another party to form a government.

The chief whip of the Pheu Thai party, which last week suffered the loss of its prime minister, Paetongtarn Shinawatra, to a court ruling, said the party had decided to forge ahead with seeking a snap election.

Moments earlier, the opposition People's Party, which controls nearly a third of lower house seats, said it was backing the rival Bhumjaithai party's ambitious leader Anutin Charnvirakul for premier, a potential game-changer that could break days of political deadlock.