Hungarians were set to return Prime Minister Viktor Orban to power for another four years in a parliamentary election on Sunday that was also expected to entrench the far-right Jobbik party as a political force.
Orban, 50, has had repeated rows with the European Union and foreign investors, particularly over heavy taxes imposed on the country's mostly foreign-owned banks, telecoms and energy firms, and increased state control over the energy sector.
But he is popular with many voters for stabilizing public finances and cutting their electricity and gas bills. Opinion polls show his Fidesz party is on course for a landslide victory.
"I would like to see high turnout because that would allow stronger governing," Orban told Reuters after he cast his vote early at a school in the capital.
"I hope many voters will go to cast their votes, and whatever government is formed, it can start working ...with strong public support," he added.
Two questions remain: whether Orban can retain his two-thirds majority in parliament, which allows him to change the constitution, and whether Jobbik can make a late surge and overtake the leftist opposition to become the second biggest political force.
A good result for Jobbik, accused by critics of being anti-Semitic and stoking antipathy toward Hungary's Roma minority, could be a harbinger of how other nationalist right-wing parties perform in European Parliament elections next month.
Public support for Orban's Fidesz stood at 34 percent a week before the vote in a survey by pollster Ipsos, a leftist alliance led by Socialist party Chairman Attila Mesterhazy scored 20 percent and Jobbik was third with 14 percent.
Investors in Hungary can expect more unpredictable and, for some, hostile policies if Orban wins the election, according to a Reuters poll and sources with knowledge of his intentions.
Orban has pledged to stick to his policies if reelected, continuing to cut energy prices and getting rid of foreign currency mortgages that are burdening households. Foreign banks fear this could inflict further losses on them.
More unpredictable policies could weigh on the forint, especially if the central bank - led by a strong ally of Orban's - cuts interest rates further from record lows, against a backdrop of jittery sentiment in global markets.
"A Fidesz-led government would guarantee long-term political stability and policy continuity," Blanka Kolenikova, Senior Analyst at think tank IHS Country Risk, said in a research note.
"However, it would further erode the investment and business environment, undermining Hungary's competitiveness towards its regional peers."
Critics say Orban has used his mandate to curb democratic checks and balances and the freedom of the media, allegations his government rejects.
Voting at over 10,000 polling stations began at 0400 GMT and polls close at 1700 GMT. An unofficial result will be announced on Sunday night.
Unlike four years ago, when Hungarians voted in two rounds, Sunday's election will feature a first-past-the-post single round in 106 constituencies, with the number of lawmakers in parliament reduced sharply to 199 from 386.
Ethnic Hungarians in central Europe, locked outside Hungary's redrawn borders after World War One, will vote for the first time, although they are not likely to have a major impact on the election's outcome.
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