Greek leaders cobbled together a last minute deal on austerity cuts on Thursday, clearing the way for the eurozone to decide on a bailout package as unions called a new strike against the terms.

"There is a general agreement on the contents of the new programme," the government said in a statement, referring to a eurozone bailout worth 130 billion euros ($171 billion) that officials have laboured on since October.

The announcement came just hours before eurozone finance minister were due to meet on the accord and a debt rescue aiming to avert a Greek default and end a bitter chapter in the eurozone crisis.

A deal by private sector banks to write-down their holdings of Greek debt by half was also at hand, an EU diplomat said.

The government coalition parties balked overnight at cutting another 650 million euros, around half of it from supplementary pensions, and argued until almost the last minute on Thursday over finding savings in other areas of the budget.

"Consultations with the troika on the issue left open for further discussions were successfully concluded this morning," the government said, referring to talks with EU, International Monetary Fund and European Central Bank officials.

"The political leaders agreed with the result of these consultations," it added without giving further details.

The message from Brussels meanwhile was that the shortfall in the budget, however small, had to be bridged and by whatever means.

European Central Bank chief Mario Draghi told reporters in Frankfurt that he had received a phone call from Greek Prime Minister Lucas Papademos telling him "that agreement has been reached and has been endorsed by major parties."

An EU diplomat told AFP there is also "consensus" on the voluntary writedown by private creditors of their holdings of Greek bonds -- "the biggest debt restructuring ever."

Private creditors, who are negotiating an exchange of bonds that will save Greece at least 100 billion euros, are to meet on Thursday in Paris before the Europgroup finance ministers meeting.

Greece has run up total debt of about 350 billion euros, roughly 160 percent of its gross domestic product, and the IMF has insisted that level be brought down to a maximum of 120 percent in 2020 in order for a further bailout to go ahead.

The deal would likely see the face value of the 200 billion euros in bonds that private creditors hold cut in half but their total losses may hit 70 percent given they will receive 30-year bonds at lower interest rates.

The bond exchange will take several weeks to perform, raising concerns whether it can completed before Greece faces 14.5 billion euros in payments due on March 20.

A defaults could spark a domino effect that might undermine the entire euro common currency project.

Greece hopes to cut its March repayment in half with the bond swap, government spokesman Pantelis Kapsis told NET radio.

"It would be comical and tragic to miss March deadlines, and fail to restructure that month's debt for a dispute over 300 million euros," Kapsis said, referring to the feared supplementary pensions cut.

The main private- and public-sector unions called a 48-hour general strike on Friday and Saturday to fight what they called "barbaric" new wage and pension cuts.

"We categorically reject this framework to impoverish and bankrupt society and the economy," leading union GSEE said.

According to the Greek press, the measures under consideration included slashing the minimum wage by 22 percent, sweeping cuts to salaries and pensions and 15,000 public sector job losses.

Anguish over the measures was exacerbated as official data showed the jobless rate exceeding a million people, or 20.9 percent of the workforce.

If eurozone finance ministers approve the deal at a meeting due to begin at 1700 GMT the programme of reforms will be put before the Greek parliament on Friday, ahead of a vote on Sunday.

In principle, the government coalition can rely on support from 255 of the 300 deputies but the political stakes are high as the parties prepare for early elections in April.

Far-right leader Georgios Karatzaferis, the first to emerge from the coalition talks, denounced the troika for heaping unreasonable pressure on the Greek government to enact more painful cuts to public spending.

"I made clear my intentions right at the start of the meeting. I cannot in one hour sign up to a plan which will affect the country for 40 or 50 years without receiving (legal) assurances that the measures are going to get the country out of its impasse," he told reporters.