Voters across Poland cast ballots in local elections on Sunday four months after the government of Prime Minister Donald Tusk took power, ending eight years of conservative nationalist rule in the country.

Nearly 190,000 candidates are vying for positions as mayors and councilors across the nation of 38 million people.

Recent voter surveys have shown a close race is likely between Tusk's Civic Coalition and Law and Justice (PiS), the conservative party that governed the country from 2015.

Voter turnout at 1500 GMT was 39.4%, the country's electoral commission said.

As polls closed in the evening, initial returns suggested that PiS had taken 33.7% of the vote, bettering Tusk's KO, which had 31.9%. Other governing coalition parties Third Way and the Left scored 13.5% and 6.8% respectively.

The results are being closely watched in Brussels ahead of the European Parliament elections in June.

Litmus test for liberal pro-European stance

The vote is being seen as the first electoral test for Tusk's coalition government.

Tusk has pledged to reverse the previous government's changes to the judicial system and public media, which were seen by the European Union as violating its democratic standards.

This led to frequently strained relations between Warsaw and Brussels.

However, change in several areas has been slow in coming, as new legislation will be needed, for example, to give the judicial system back its independence.

The strict abortion laws introduced by the PiS are also supported by some conservatives in Tusk's own coalition, hampering reforms.

Nonetheless, the reforms enacted by Tusk have already led to the unblocking of billions in EU funds that were frozen over the bloc's concern about the state of the rule of law under the PiS.

Tusk warns of backsliding

The prime minister himself has warned that a win for his liberal Civic Coalition (KO), the largest grouping in the ruling alliance, is vital to prevent Poland from slipping toward a return to the nationalist rule of the PiS.

"Our dream — once a beautiful dream, and today an increasingly better reality — may end overnight," he told a rally in Warsaw on Friday.

"If someone believes that freedom, human rights, women's rights, democracy, free economy, self-government — that all this is permanent, will defend itself ... we will lose it all again."

The PiS has repeatedly rejected accusations that it undermined democracy and human rights during its time in power.

PiS leader Jaroslaw Kaczynski has called on voters to show Tusk's government "a yellow card" — a warning given to players by soccer referees.

 A second round of voting in mayoral races will be held on April 21.

 tj/lo (Reuters, AP)