ZAGREB - Croatians cast ballots on Sunday to elect a president under the cloud of a deep economic crisis, with incumbent Ivo Josipovic seen as the frontrunner as he sought a second term leading the EU's newest member state.

Surveys ahead of the vote showed that of the four candidates vying for the largely ceremonial post, the 57-year-old centre-left leader had only one serious rival: Kolinda Grabar-Kitarovic of the main opposition conservative HDZ.

With none of the candidates expected to win more than 50 percent outright, a run-off round on Jan 11 is likely. Social Democrat PM Zoran Milanovic, who voted in downtown Zagreb, voiced hope that bad weather and snow that hit most of the country Sunday overnight would not affect turnout. At 1030 GMT, four and a half hours after polling stations opened, turnout was 13.19pc, the electoral commission said.

It was some two percent more than at the same time five years ago.

The soft-spoken Josipovic - the popular third president of the former Yugoslav republic since independence in 1991 - is a member of Milanovic's Social Democratic Party (SDP), the main partner in the ruling coalition.

A former law professor who won office on an anti-corruption ticket, Josipovic famously played Beethoven's "Ode to Joy" on piano when Croatia joined the European Union in 2013 hoping membership would revive its flagging economy.

But the tourism-reliant economy of the small Adriatic nation of 4.2 million remains one of the EU's weakest after six years of recession.

Unemployment is close to 20 percent, half of the country's youth are jobless and public debt is close to 80 percent of gross domestic product (GDP).

The centre-left government has been accused of failing to carry out the necessary reforms to address the country's huge and inefficient public sector or improve the investment climate.

Weighed down by the SDP-led government's unpopularity and accused by critics of not taking a clear stance on major issues, Josipovic has taken firmer attitudes in the months leading up to the vote.

On the economic front, he has pledged a "better economy with jobs for every young person".

Mario Rozankovic, a voter from Zagreb in his 30s, said he supported Josipovic because he viewed him as "honest, respectable, intelligent and capable".

Though the president has limited powers - running the country is primarily left to the government - Sunday's election is seen as a key test for Croatia's political parties ahead of parliamentary contests in late 2015.

A victory for Grabar-Kitarovic would further boost the position of the HDZ, currently the most popular party.

The 46-year-old, who represents moderates within HDZ, is a former foreign and European affairs minister and an ex-NATO assistant secretary general.

During the campaign she slammed Josipovic's lack of initiative on tackling economic hardship.

"He shares the blame with the government for a bad (economic) situation in the country since he remained silent and did nothing," Grabar-Kitarovic said.

Meanwhile, HDZ head Tomislav Karamarko said that her victory would "mark the start of a process of (economic) changes" that would be completed with an HDZ triumph in parliamentary elections next year. "Life in Croatia is difficult," he said after voting in Zagreb, referring to the economic woes.

Ivan Janjic, a clerk in his 40s, backed the HDZ candidate. "She is a genuine patriot who left a good job abroad to help her country," he said.

The other two candidates in the race, whose chances according to polls were very slim, are rightist Milan Kujundzic and activist Ivan Vilibor Sincic, who is known for fighting against forced evictions for people who fall behind on debt repayments. Polling stations were to close at 1800 GMT and first partial results were expected late Sunday.