* Centrists hold narrow lead in polls
* PM Orban pledges fiscal conservatism
* Leftist PSD regains some rural support
* Roughly 12% of Romanians voted by 1020 GMT (Adds early turnout, voters)
By Radu-Sorin Marinas and Luiza Ilie
BUCHAREST, Dec 6 (Reuters) - Romanians began voting on Sunday in a national ballot key to restoring credibility among investors, with the incumbent, reform-oriented centrists of Prime Minister Ludovic Orban holding a narrow lead over opposition Social Democrats.
In power for a year in spite of his opponents' hold over parliament, Orban, 57, has said he would tone down a 40% pension hike ordered by the leftist PSD, which economists said would propel the deficit into double digits and push Romania's credit rating to junk.
He has pledged to halt efforts by leftist-led cabinets to sap court independence amid the judiciary's scrutiny of alleged corruption and misuse of funds - accusations the PSD denies.
Orban also campaigned on a promise to bring Romania closer to the European mainstream following years of fiscal populism and political instability coupled with neglect of rundown infrastructure and public services.
"I have voted for substantial reforms, for a clear Euro-Atlantic direction for Romania and ... for a development plan that will give Romania the lift it deserves," Orban told reporters on Sunday.
By 1020 GMT, just over 2.2 million Romanians had cast their votes, or 12.4% of the electorate.
"I voted with the hope that we will finally manage to accumulate a majority that will lead this country properly," said Eugen Dorobantu, a 70-year-old structural engineer.
More than 18 million Romanians are eligible to vote, but analysts expect turnout of about 40% due to pandemic fears.
Opinion polls give Orban's PNL about 28-30% of the vote and 24-26% for the PSD. A September poll put PNL at 35% against PSD's 20%.
If it wins on Sunday, the PNL is expected to seek a governing coalition with progressive USR-Plus party, running on 15-17%. Analysts warned the two groupings might struggle reach agreement on transparency and key appointments.
The Romanian leu has traded near all-time lows against the euro in the last year, weighed down by twin deficits and a string of corruption-related scandals which toppled three governments since the last parliamentary election in 2016.
All three main rating agencies have Romania on the lowest investment grade with a negative outlook.
One year after the government it led fell in a no-confidence vote, the PSD has clawed back support in recent months, amid anxiety among its core rural electorate over Orban's fiscal conservatism.
The coronavirus pandemic has also fuelled anger over social distancing restrictions that have hit thousands of small farmers who sell their produce in nearby cities.
"I came for my right to vote ... but there is turmoil in my thoughts, I have nobody to vote for," said 67-year-old pensioner Viorica David.
"We are leading a life of nightmare, especially us pensioners. I worked for 44 years and yet everybody sets us aside, absolutely everybody. I hope all of them get to retire and get treated as we are treated now, nobody has place for us."
(Additional reporting by Octav Ganea; Editing by Raissa Kasolowsky)
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