A debate on Greece's budget for next year heated up in Parliament on Saturday ahead of a crucial vote that was expected to push the bill into law despite the opposition of several coalition lawmakers to further tough economic measures.

The vote was widely expected to pass as the government retains a four-seat majority in Parliament, and a more controversial bill on a new unified property tax is to be submitted separately next week. But government officials were keen to secure the backing of skeptical coalition lawmakers. Late on Friday, Prime Minister Antonis Samaras met with several conservative lawmakers in a bid to boost their morale, according to sources.

Samaras was to address Parliament shortly before the vote, scheduled for midnight on Saturday, in a speech expected to focus on his government's forecast of a gradual economic recovery from next year. The budget for 2014, which does not have the backing of the troika, predicts that Greece will post a primary surplus this year and next. Leftist SYRIZA has challenged the economic indicators presented by the government, pointing to the devastating repercussions of austerity on Greek society, a theme party leader Alexis Tsipras was expected to return to in his scheduled speech on Saturday night.

The country's two main labor unions are to hold an anti-austerity protest outside Parliament on Saturday evening, gathering from 6 p.m.

Earlier in the day, lawmakers from conservative New Democracy and SYRIZA clashed in Parliament. SYRIZA MP Stathis Panagoulis claimed that the government's policies have pushed Greece back to the 1930s and the Nazi occupation. He referred to a spate of fires that have broken out in recent weeks in poor households that lack electricity and use alternative forms of heating such as braziers.

"I suggest that you prepare yourselves psychologically because in a few months you will have to sit on the benches of the political opposition," Panagoulis said. ND's parliamentary spokesman Manolis Kefaloyiannis responded by warning that the leftists would "burn out" in their efforts to get into government.

Tensions are expected to rise further in the House in a debate expected to begin on Tuesday when a controversial unified property tax is to be submitted to Parliament. The bill has been revised due to objections by dozens of coalition deputies with some still wavering. A legislative amendment foreseeing the extension of restrictions on home foreclosures is expected to be tabled on the same day. Leftist SYRIZA has proposed an alternative amendment foreseeing a one-year extension to a current ban on foreclosures on primary residences with an objective value of less than 200,000 euros.