Australia's opposition Labor party pulled off a huge electoral turnaround in a key state on Saturday, positioning it to oust the ruling Liberal-National Party in a voter backlash that threatens the future of Prime Minister Tony Abbott.

Abbott said Sunday his government had "lessons to learn" from the rout in Queensland amid growing leadership questions after his unpopular move to knight Britain's Prince Philip.

Rumors of challenges to Abbott's position as prime minister have emerged over the past week after the knighthood decision. But the demise of the Liberal-National coalition in Queensland's elections Saturday has piled further pressure on him.