Prime Minister Viktor Orban's Fidesz party is favored to win Hungary's parliamentary elections by a wide margin on Sunday, with a left-wing coalition and the far-right Jobbik party vying for second place.

Orban, who is seeking his third term, said he hoped for a heavy turnout to give legitimacy and a clear mandate for the future.

"It allows the government to do a more vigorous job," Orban told reporters after casting his ballot in a school near his home high in the Buda hills. "I hope very many people will vote so no matter what kind of government there will be, it will start its job with large popular support."

Fidesz and its smaller ally, the Christian Democrats, won a two-thirds majority in 2010 which allowed them write a new constitution and pass legislation unchallenged. Orban has been asking supporters to ensure another super-majority for his government so it can continue with its policies unopposed.

Polls taken days before the elections showed Fidesz favored by up to 51 percent of likely voters. The party's voters are also considered more disciplined and likely to vote.

Former Prime Minister Gordon Bajnai, now part of a five-party left-wing coalition, said the elections would determine whether Hungary "will again be a peaceful European country" and return to its past path toward Western values — or drift further toward the East.

His remarks allude to concern over a major nuclear power deal with Russia. Orban's government has signed a contract to have a Russian company build an extension to Hungary's sole, Soviet-built nuclear power plant, which produced half of Hungary's electricity last year. Russia is also giving Hungary a 10 billion euro ($13.7 billion) loan for the project — the main reason given by the government as to why the deal was signed with little prior consultation.

The agreement is seen as part of Orban's efforts to establish closer relations with countries outside the European Union, including nations unlikely to fault the government for its weakening of the system of democratic checks and balances.

Bajnai also reiterated the opposition's claim that, because of a new electoral system created by Fidesz, Sunday's elections could be considered "free but not honest."

Among the new rules seen tilting the playing field were strict limits on campaign ads by political parties but not on government propaganda and a redrawing of districts.