Poland's ruling Law and Justice party under its leader, Jaroslaw Kaczynski, the prime minister, on Sunday night admitted defeat in the country's hard-fought parliamentary elections, putting an end to two turbulent years in government.

Civic Platform, Poland's main opposition party, claimed victory after it emerged as the biggest single party and prepared to form the next government under its leader, Donald Tusk.

The outcome was a dramatic reversal for Mr Kaczynski and his twin brother President Lech Kaczynski, who have ruled Poland since 2005, polarising politics and repeatedly running into conflicts with Poland's European Union partners.

Exit polls show Civic Platform with 44 per cent of the vote, and Law and Justice (PiS) well behind on 30-31 per cent. Also winning seats in the 460-member parliament were the Left and Democrats, an amalgam of post-communists and intellectuals from the Solidarity labour union, with about 13 per cent of the vote, and the leftwing Peasants party with 8 per cent. Voter turnout was above 55 per cent, one of the highest since 1989, as many Poles were galvanised to vote against the Kaczynskis.

Mr Tusk told a cheering crowd of supporters: "Poles voted for a better government and a better life."