Greek voters enraged by economic hardship will punish traditional parties in a highly uncertain election on Sunday that could plunge the country into new political chaos and shake the entire euro zone.

At stake is whether Greece sticks with the harsh terms of a hugely unpopular 130 billion euro ($170.83 billion) EU/IMF bailout, or heads down a path that could see it ejected from the single currency, with dire risks for other EU peripheral states like Spain and Italy.

Wages and benefits have been slashed, unemployment has rocketed and thousands of businesses have collapsed. Furious Greeks have been turning to small, anti-bailout parties to punish traditional politicians they blame for the crisis.

A record 8-10 parties are expected to enter parliament, and public outrage with the main parties could turn at least four small groups into potential power-brokers.

The last polls published before the election showed the conservative New Democracy and socialist PASOK parties - which between them dominated Greece for decades and now rule jointly - would scrape just enough votes to renew their uneasy coalition. They are the only parties to support the bailout.

No new surveys have been allowed to be published for two weeks and pollsters warn the result may be a surprise.

"We voted for them since the 1980s and we feel cheated," municipal worker Christina Theodorakou, 50, said of the two big parties. She has seen her monthly salary cut by 500 euros since the crisis began.

"We built a life over the years and they destroyed it overnight. Their campaigns are addressing idiots. I'll vote for a small party," she said.

Her daughter Alexandra, 18, a nursing student who was joining her for lunch in the western port city of Patras, is old enough to vote for the first time but said she probably wouldn't bother: "Why go? Nobody can promise us a better future."