Australian Prime Minister Malcolm Turnbull and maverick nationalist politician Pauline Hanson faced questions about their leadership on Monday after their parties suffered a resounding defeat in a state election at the weekend.

Turnbull had already been trying to fight back against plummeting opinion poll numbers and leadership dissent within his center-right Liberals, the senior party in the ruling Liberal-National coalition, before the opposition Labor party scored a landslide win in the Western Australia state election.

Support for Turnbull is at its lowest since he grabbed power in a party-room coup in September 2015 and party disharmony has been magnified as voters abandon the mainstream amid a resurgence among far-right parties such as One Nation.