The first day of voting for Croatia's seventh parliament at polling stations outside the country where Croatian nationals with no permanent residence in Croatia can vote for their three representatives in the Sabor passed calmly with a low turnout, the election monitoring nongovernmental organisation GONG said on Saturday.

By 7.30pm, GONG received about 30 reports from citizens about various forms of election blackout breaches, mainly from Zagreb and east Croatia, but also from Bosnia and Herzegovina. There was campaigning against certain political parties and candidates.

The breaches were committed by both bigger and smaller parties by distributing gifts with the party's insignia, putting up posters, distributing leaflets, even outside a polling place abroad, sending text and posting Facebook messages suggesting which party to vote for, including over the telephone. GONG also received a report that a representative of the Catholic Church had suggested who to vote for during Mass in a town in east Croatia.

Twenty-seven GONG observers are watching the out-of-country voting - 19 in Bosnia and Herzegovina, three in Serbia, two in the Netherlands, and one in Switzerland, Germany and Canada each.

GONG once again reminded all political parties and candidates running in the election of the obligation to refrain from any electioneering until polling stations close at 7pm on Sunday.

Some 4.5 million Croatians went to the polls on Sunday for parliamentary elections.

More than 6,500 polling stations across the country opened at 7 a.m. local time (0600 GMT) and will be closed at 7 p.m. (1800 GMT).

A total of 4,359 candidates are running for 151 seats in the parliament. Preliminary results are expected at midnight.

Croatia is set to join the European Union in July 2013. Sunday's elections will decide which party or coalition will lead the former Yugoslav republic to become the bloc's 28th member.

Latest opinion polls showed the ruling Croatian Democratic Union plagued by corruption scandals will be ousted by the opposition coalition led by the Social Democratic Party.