If the deadlock does not ease, Greece faces new elections under a caretaker government in mid-June, about the time it has to detail new drastic austerity measures worth €14.5 billion ($19 billion) for 2013-14.
Analyst Vangelis Agapitos said protracted instability would threaten the country's eurozone membership. Greece's debt inspectors — the eurozone, IMF and European Central Bank, collectively known as the troika — could turn the screws by halting release of the bailout funds until Athens moves forward with its pledged reforms.
"Europe can live without Greece but I don't think Greece can live without Europe," he said. "If the troika is bluffing, Greece will remain in the euro. But if the troika says: 'I can negotiate, but first show me some progress,' Greece has no progress to display right now."
"If the troika rattles our bars, then either the people will come to their senses at the next elections or the country will enter an alternative course, and when we open that door we will see what kind of chaos — or paradise — lies behind," Agapitos said.
Sunday's big winner was the anti-bailout Radical Left Coalition, or Syriza, whose unprecedented second place with 16.78 percent gives it 52 seats.
Disaffected voters deserted PASOK and New Democracy, the two mainstays of Greek politics, leaving them at their worst level since 1974, when Greece emerged from a seven-year dictatorship. Instead, strong gains were registered by smaller parties, including the extremist Golden Dawn, which rejects the neo-Nazi label and insists it is nationalist and patriotic.