Greek interim coalition government faced turbulence, after the resignation of six cabinet ministers on Friday evening over a new package of austerity measures promoted in order to secure further international rescue loans in time to avoid a Greek bankruptcy this spring.

The government crisis erupted as the two main labor unions of public and private sector employees ADEDY and GSEE intensified anti-austerity protests.

A new 48-hour general strike which has paralyzed the public sector was launched on Friday and a string of demonstrations were staged nationwide ahead of a critical parliamentary vote on Sunday on the harsh terms of the bailout deal clinched earlier this week.

Greek Prime Minister Lucas Papademos urged the parties supporting his three-month-old administration to make the right choice and push through the measures. Otherwise, Greece faces "a catastrophe," he warned, addressing the cabinet on Friday night.

"Default is not an option we can allow to happen," he underlined.

Papademos argued that the social cost of the fresh pay cuts and reforms demanded by EU/International Monetary Fund (IMF) creditors in return of an 130-billion-euro (171.59 billion U.S. dollars) aid pact, the second since 2010, will be smaller in comparison to a chaotic collapse.

Under the burden of a 360-billion-euro sovereign debt, the eurozone member country faces bankruptcy on March 20, when it will be asked to repay 14.5 billion euros in maturing bonds.

In such a case, according to political analysts in Athens, a Greek exit from the eurozone is regarded as a certainty, as the entire European common currency zone will face a major impact and global economy could sink in recession.

Besides mounting pressure by European partners and IMF over the past few days for a swift and clear commitment to the austerity and reform drive by the next Euro group meeting on Wednesday, Papademos' administration faces the prospect of a cabinet reshuffle in coming days or collapse, according to local analysts.

They expressed doubt whether the parliament will pass the measures and the transitional administration will survive, as an increasing number of lawmakers of the coalition partners warned with negative votes.

The political crisis unravelled following the announcement earlier on Friday of George Karatzaferis, head of the rightist Popular Orthodox Rally (Laos), the smallest party in the coalition government, that his party will vote against the austerity package and debt agreement at the parliament. He denounced the "country's humiliation by Europe."

By the evening the four ministers of Laos in the government -- Transport Minister Makis Voridis, Deputy Shipping Minister Adonis Georgiadis, Deputy Defense Minister George Georgiou and Deputy Agriculture Minister Asterios Rondoulis -- had tendered their resignations.

Alternate Foreign Affairs Minister Marilisa Xenoyiannakopoulou of the socialist PASOK party became the sixth minister who resigned over the further austerity measures. Deputy Labor Minister Yiannis Koutsoukos from PASOK had started the wave on Thursday evening.

The parliamentary groups of PASOK and New Democracy, the conservative party in the coalition administration, will be holding crucial meetings on Saturday, as an increasing number of deputies has warned to vote down the debt deal.

In order to secure a positive vote, according to local media reports, party leaders are expected to announce that a negative vote would result in expulsion from the party.

Three months ago technocrat Papademos' administration had easily won a confidence vote with a 250-seat majority in the 300-member strong assembly, with the support of the three parties.

He was appointed at the helm of the wider consensus government to reach and push through the parliament a fresh debt deal that will also open the way for a write-down of part of the Greek debt owned by private creditors, before leading the country to snap general elections.

Initially the polls were scheduled for late February and then pushed back to April due to the delays in negotiations with creditors. Political analysts in Athens said on Friday that eventually Greeks could go to the polls earlier, as the administration faces enormous pressure.

Shortly before the outbreak of the government crisis, thousands of strikers had encircled the parliament building denouncing the belt-tightening measures and planned layoffs of tens thousands civil workers.

This mix of policies imposed by lenders strangles Greek people, fuelling deep recession and unemployment that has reached record high rates over the past two years, since the start of the debt crisis, they said, chanting anti-austerity, anti-government and anti- EU/IMF slogans.

The peaceful march of over 10,000 demonstrators ended in violent clashes between hooded youth and policemen that resulted in three injuries and over a dozen arrests amidst rock pelting and tear gas.

Police forces are on alert ahead of new rallies scheduled for Saturday and Sunday in front of the parliament.