By Sam Cage and Angel Krasimirov
SOFIA (Reuters) - Ruling party candidate Rosen Plevneliev is set to lead in the first round of Bulgaria's presidential election on Sunday, but probably will need a run-off to secure the position after a campaign marred by protests and violence.
It will tighten the center-right GERB's grip on power in the European Union's poorest country, though polls show its popularity has slid to about 30 percent, from some 40 percent when it took power in 2009.
Rallies against the Roma minority and corruption rocked Bulgaria's cities last month and a bomb last week blew up the car of a popular journalist, highlighting GERB Prime Minister Boiko Borisov's struggle to address unemployment, graft and the fragile position of ethnic minorities.
The Organization for Security and Cooperation in Europe (OSCE) is monitoring the election as there are some concerns over vote buying given Bulgaria's ranking as the EU's second most corrupt country.
"It's clear there is no alternative to GERB," businessman Todor Valkov, 43, said after voting. "The Bulgarian judicial system is ill, it's so corrupted. It's time to get rid of so many people."
The first indication of the results will be exit polls at about 1600 GMT and official results are expected on Monday morning. Local elections will also be held on Sunday.
While the presidential role is largely ceremonial, a Plevneliev win -- replacing incumbent Socialist Georgi Parvanov -- would remove potential for a high-profile dissenting voice and the threat of vetoing legislation.
Borisov so far has failed to make the promised and much-needed reforms of healthcare, labor and public administration and analysts say he is unlikely to change tack, even with Plevneliev alongside, before 2013 general elections.
"A victory for Plevneliev will place GERB in a commanding position ahead of the legislative election scheduled for 2013," James Goundry, an analyst at consultancy IHS Europe, said.
Plevneliev has pledged to step up efforts to crack down on corruption and organized crime, improving public sector transparency and getting serious about seizing illegally obtained assets.
"I know what Bulgaria, the regions, the economy need so that we can be a respectable member of Europe, respectable member of the world," Plevneliev was quoted as saying by local media after casting his ballot.
Rather than pushing potentially unpopular reforms, Borisov is more likely to focus on sustaining tight fiscal discipline, which wins praise abroad but does little to improve the lot of Bulgarians, who have an average wage of 350 euros a month.
Any unhappiness with GERB has so far not translated into support for the nationalist Attack party, which came second in the 2006 presidential race, but is now languishing on just four percent in polls.
They show Plevneliev will probably need a second round to gain more than 50 percent of the vote, his most likely opponent being Socialist Ivailo Kalfin, a former foreign minister.
Former EU Commissioner Meglena Kuneva, an independent who is expected to gain support from voters dissatisfied with the political establishment, is in third place.
(Editing by Michael Roddy)