Poland is voting in parliamentary elections that could give incumbent Prime Minister Donald Tusk and his center-right Civic Platform four more years to pursue economic reforms and improved ties with the rest of Europe.

Voters are electing 460 members of the lower house of parliament and 100 members of the senate. The party winning the most seats will form a new government.

Opinion polls in the past week showed Mr. Tusk's party favored by 31 percent of respondents, and the opposition conservative Law and Justice Party of former Prime Minister Jaroslaw Kaczynski with 21 percent.

Analysts say no party will win an outright majority, and those predicting a Tusk victory say he will likely be forced to form a ruling coalition similar to the one forged with the Peasants' Party after 2007 polls.

Official results are expected by early Monday.

Pre-election polls also indicated that three other parties would also win parliamentary seats in the election. The new socially and economically liberal Palikot Support Movement, the Democratic Left Alliance and the current coalition partner, the Polish People Party.

A Civic Platform win Sunday would mark the first time a party has held on to power in the country's six general elections since the fall of communism in 1989.

Poland is the only member of the 27-member European Union to navigate the global recession of 2008 and its aftermath with positive growth.