A Greek nationalist party on Friday said one of its deputies had been offered between 2 and 3 million euros to influence his vote in a critical presidential election.
The Independent Greeks party said a former bank employee it did not identify, had attempted to bribe its deputy Pavlos Haikalis, a popular actor.
The party testified to a magistrate that 2-3 million euros ($2.5-3.7 million) was offered, a judicial source said.
"I was approached by a man...who plays an active role in politics," Haikalis told a news conference.
"I thought it was a joke at first," he said.
Independent Greeks leader Panos Kammenos said the alleged bribery attempt had been captured on video and the footage sent to judicial authorities.
The suspect, Kammenos said, was known to top government officials and was later employed by Greece's Piraeus Bank.
Government spokeswoman Sofia Voultepsi dismissed the affair as "poorly acted theatre" and demanded that the footage be publicised.
Failure to elect a new president by December 29 will precipitate early elections in bailed-out Greece.
European Union and International Monetary Fund officials fear the ballot will be won by radical leftist party Syriza and undo the country's ongoing fiscal reforms.
The looming political stalemate has alarmed international markets, pushing up the yield of Greek bonds and prompting EU Commission chief Jean-Claude Juncker to recently warn the nation against delivering the "wrong" election result.
In the first round of the presidential vote on Wednesday, the government candidate -- former EU commissioner Stavros Dimas -- mustered 160 parliamentary votes out of the required 200.
A total of 200 votes are again required in a second vote on Tuesday. The bar lowers to 180 votes in a third and final vote on December 29.
The Independent Greeks party recently claimed that another of its deputies had been offered money to help elect a president, but an investigation found insufficient evidence to press charges.