Sweden's first female prime minister, Social Democrat Magdalena Andersson, has resigned after less than 12 hours in office when her coalition collapsed, plunging the country into further political uncertainty.

Andersson said a decision by the Green Party, the smaller party in the coalition, to resign had forced him to resign. She added that she had told the speaker of parliament that she hoped to be re-appointed prime minister as head of a one-party government.

The Green Party said it would leave the government after the coalition budget bill was rejected by parliament.

"There is a constitutional practice that a coalition government should resign when a party withdraws," Andersson told reporters. "I do not want to lead a government whose legitimacy will be questioned."