Greek lawmakers have approved the government's £26 billion austerity bill in a vote in parliament on Thursday, paving the way for a record bailout from the European Union and International Monetary Fund.
As the vote took place, a crowd of thousands of protesting students, workers and pensioners gathered outside parliament to voice their opposition to the bill, chanting "Take to the streets! Say 'No' to the measures!"
Riot police fired tear gas to disperse about 150 protesters who hurled bottles and stones. The demonstrators set rubbish bins on fire as they withdrew.
Speaking to the house before the vote, Prime Minister George Papandreou said there was no time to lose in reforming Greece's broken economy, whose debt and deficit problems have triggered a wider crisis threatening the entire 16-nation euro zone.
"The emergency measures are the condition for us to regain our credibility and win time, lost time. The time to make the big changes that were delayed for years," he said.
The legislation, which includes tax hikes, pension reforms and deep cuts in public sector bonuses which will slash take-home pay for a fifth of the workforce, is being pushed through in exchange for aid of £94 billion - the first rescue of a member of the common currency bloc.