Greek police have used water cannon and tear gas to quell violent protests, as politicians voted to impose fresh austerity cuts.
Around 100,000 protesters marched to the main square outside the parliament building in Athens to protest the £10.7bn cuts and reforms essential to unlock further monetary aid.
The measures are for 2013/14 and include new, deep pension cuts and tax hikes, a two-year increase in the retirement age to 67, and laws that will make it easier to fire and transfer civil servants who are currently guaranteed jobs for life.
The violence broke out after protesters tried to break through a barricade to enter the parliament building.
TV footage showed smoke and small fires around the building as protesters threw petrol bombs and police responded with stun grenades.
Prime Minister Antonis Samaras is expected to win a close decision, despite intense opposition.
"Today we must confirm Greece's new credibility," Mr Samaras said. "We choose whether we want to stay in the eurozone ... or return to the drachma. That is the choice."
But Panagiotis Lafazanis, of the main opposition Syriza, said: "You are throwing people onto to the street, people who need a few more years till they get their pensions.
"What will happen to them? Will they starve? This is an illegal and unconstitutional law."
Public transport has been halted, schools banks and government offices were shut down and rubbish is piling up on the streets on the second day of a nationwide strike.
Parliament staff had delayed the vote after going on strike to protest against wage cuts.