By Lefteris Papadimas and Renee Maltezou
ATHENS (Reuters) - Greek lawmakers failed to elect a new president in a first round of voting on Wednesday, leaving Prime Minister Antonis Samaras still looking for as many as 20 votes from independents and small parties to keep his coalition government in office.
With two more rounds still to come, a win for the government had not been expected on Wednesday but the result was at the lower end of expectations, just meeting the minimum threshold officials had seen as satisfactory before the vote.
Of the 300 members of parliament, 160 voted in favour of the government's candidate Stavros Dimas with 135 against and five absent, short of the 200-vote supermajority needed to elect a president in the first round.
Greek media had speculated the government could win between 161 and 167 votes but only five deputies crossed the floor to vote with the 155 members of the ruling coalition.
The head of state is a largely ceremonial post but failure to elect a president with a three-fifths majority in parliament triggers early elections. Polls suggest they would be won by the leftist Syriza party, which promises to scrap Greece's international bailout accord.
A stony-faced Samaras said he hoped parliament would elect a president in the two remaining rounds of voting on Dec. 23 and Dec. 29 and avoid an early national election that would have to be held if it does not.
"Conditions are difficult, Greek lawmakers are aware that the country cannot afford adventures," he told reporters as he left the chamber.
Syriza leader Alexis Tsipras said the government's "strategy of fear" had collapsed. "Democracy cannot be blackmailed," he told reporters after the vote.
A second round of voting will be held on Dec. 23 and a final round on Dec. 29, when the threshold needed for victory falls to 180.
Syriza has been ahead of the government in opinion polls for months but its lead has shrunk in recent days as the showdown in parliament has neared, bringing the prospect of weeks of instability.
Polls suggest that most Greek voters, weary after years of austerity, do not want early elections just as their battered economy is showing signs of revival.
Greece's euro zone partners are fear a victory by the anti-bailout party could trigger trouble in the currency bloc, although it is political fallout rather than financial that is foremost on their minds.
The final result of the parliamentary vote will depend on about two dozen independent lawmakers, possible rebels among the small Democratic Left party, which quit the ruling coalition last year and now has 10 deputies, and the right-wing Independent Greeks party which has 12.
As manoeuvring continued, speculation grew over possible alternative proposals, including a deal that could involve a commitment by the government to hold elections later next year in exchange for support in the presidential vote.
Before the vote, Evangelos Venizelos, the leader of centre-left coalition partner PASOK, said he was ready to hold talks with opposition parties over possible concessions, saying "we are open to discussing everything".
One independent lawmaker said he hoped the government would be open to a deal that would see a president elected in exchange for an agreement on an election date.
"The minimum is to elect a president and set a date for national elections in 2015," Spyros Lykoudis told Greek state television after the vote.
Fears of a new chapter of prolonged political uncertainty have sent Greek stocks and bonds crashing since Samaras last week announced the presidential vote would be held this month instead of February. Greek stocks fell over 20 percent in three days last week while 10-year bond yields leapt over 9 percent.
(Additional reporting by George Georgiopoulos and Lefteris Papadimas; Writing by Deepa Babington and James Mackenzie; Editing by Andrew Roche)