Workers in Poland put out ballot boxes and national flags at polling stations on Saturday, preparing for a vote that will determine whether the centrist Civic Platform party gets another term after four years of strong economic growth _ but high unemployment.

As the country prepares for parliamentary elections Sunday, opinion polls show Prime Minister Donald Tusk's party in the lead, but facing a tough challenge from Law and Justice, the conservative party of Jaroslaw Kaczynski.

It will be a major test for Tusk, who has presided over a period of remarkable growth and helped steer the state during Poland's worst tragedy in decades _ the 2010 plane crash in Russia that killed President Lech Kaczynski and many others political and military leaders.

To his supporters, Tusk is a moderate leader who has promoted stability and good relations with Germany, Russia and the European Union. They point to the fact that the economy has grown steadily on his watch, even when the rest of Europe fell into recession in 2009.

His opponents accuse him of lacking the courage to make ambitions reforms in a country with significant problems, like high unemployment at around 11 percent and heavy state regulation that stifles businesses. The budget deficit has also grown during his term, and hundreds of thousands of young Poles who have fled to Britain and elsewhere in recent years for better wages have failed to return home in large numbers.

A joke published recently in one of the country's tabloids captures the situation. In it, one of Tusk's advisers tells him, "Mr. Prime Minster, there is a problem. According to the opinion surveys, Poles are living well and are very satisfied."

"That's great," Tusk replies. "And the problem?"

The adviser replies: "The surveys were carried out in Great Britain."

Several small parties are also vying for support. However, the main battle pits Tusk's pro-market and pro-European Union vision against that of Kaczynski. Kaczynski favors higher welfare spending and other state efforts to help the disadvantaged.

He is much more skeptical of outside powers and employs a strongly patriotic message. In past days he provoked an uproar in Poland with a new book in which he accuses Germany of trying to subjugate Poland.

The campaign has been fairly uneventful over the past weeks but began generating some emotion in recent days with Kaczynski's words against Germany, which prompted Tusk and other leaders to criticize him forcefully. They said Kaczynski was hurting Poland's national interests by threatening good ties with a key trade and political partner.

Another surprise has been the rise in support for a new left-wing party _ Palikot's Movement. It was founded by a maverick lawmaker, Janusz Palikot, who is fighting the power of the Roman Catholic church and favors other liberal causes, like support for gay rights and liberalizing the country's strict abortion laws.

Palikot's party was in third place in some recent polls, ahead of some established parties, and appears to be benefiting from disillusionment with them and increasing secularism in this conservative, mainly Catholic country.

If Tusk's Civic Platform wins on Sunday, it would make history by becoming the first to ever win two consecutive terms since the fall of communism in 1989, underlying the growing stability that has replaced the political turmoil of the early years of democracy.

However, polls show it unlikely to win enough votes to have an outright majority in parliament, meaning it would likely need to find a coalition partner. It had a good relationship with its junior partner of the past four years, the farm-based Polish People's Party.

Aside from the preparation of polling stations, the only sign Saturday of the approaching election was the absence of any talk of parties and campaigning in the media. Under Polish law, no campaigning or publishing of opinion polls is allowed on Saturday or Sunday until polls close. The aim is to give people the chance to reflect calmly on their choices before they cast ballots.

Voters in this country of 38 million will elect 460 lawmakers to the lower house of parliament, the Sejm, and 100 to the Senate.

Polling stations across the country will be open from 7 a.m. to 9 p.m. local time (0500 to 1900 GMT). Exit polls will be released when polls close but official results will only come several hours later.