Police deployed in force in Athens on Saturday for a second day of protests after the Greek cabinet approved tough austerity cuts to get international rescue funds and avoid the "chaos" of a default.

The defection-hit coalition government approved the painful belt-tightening measures in the early hours of Saturday after a day that saw renewed street clashes between protesters and riot police.

Unions have called for further demonstrations on Saturday against the unpopular measures that the EU and the IMF have demanded in return for a 130-billion euro rescue package that Athens needs to avoid default in March.

On the first day of a 48-hour general strike and protests on Friday, demonstrators hurled stones at riot police who responded with tear gas. At least 10 people were injured, including eight police officers, and six arrests were made.

"Police authorities are on alert, fearing general violence" during Saturday's protests, said the Kathimerini newspaper.

Prime Minister Lucas Papademos issued a stern warning after six members of his coalition government resigned on Friday in protest at the new cuts.

"A disorderly default would plunge our country into a disastrous adventure," he told the cabinet.

"It would create conditions of uncontrolled economic chaos and social explosion."

He warned that "sooner or later, (Greece) would be led out of the euro" and stressed: "This is an hour of historic responsibility."

The remaining cabinet members approved the deal in the early hours on Saturday and the Athens News Agency (ANA) said parliament would vote on it on Sunday. Government spokesmen could not be reached for comment.

Greece was explicitly told by its eurozone partners this week that it must agree to austerity measures in order to secure the release of further loans under a 130 billion euro ($171 billion) bailout pending since October.

Greece needs the money to stave off bankruptcy on March 20, when Athens must repay nearly 14.5 billion euros in maturing debt.

Three texts will be put to Sunday's vote: measures to recapitalise Greek banks, an authorisation for Papademos and the finance minister to sign the eurozone bailout, and a bond swap with private creditors designed to wipe out around 100 billion euros from Greece's 350-billion-euro debt, ANA said.

Details of the austerity measures will be included in a follow-up law tabled in the next two weeks, the agency said.

The measures, which include slashing minimum wages and facilitating layoffs, have sparked deep anger in a country where over a million people, or more than 20 percent of the workforce, are unemployed.

The far-right LAOS party that was part of the coalition said it would not support the further austerity cuts, and its four members in government quit.

They were followed by the assistant foreign minister for European affairs, a socialist who accused the EU of "fixation" on a labour rights overhaul.

Another socialist, a deputy labour minister, resigned on Thursday.

The government intends to appoint replacements after the measures are approved by parliament on Sunday, state television NET said.

At least five socialist and conservative deputies have declared their intention to oppose the cuts on Sunday and LAOS leader George Karatzaferis said his 16 lawmakers would do likewise.

"We are not going to vote," Karatzaferis told a news conference, adding: "Humiliation was imposed on us. I do not tolerate this."

In principle, the two senior coalition partners, socialist Pasok and conservative New Democracy, still have enough support to pass the measures.

Eurozone finance ministers on Thursday delayed a decision on a new bailout, giving Greek officials less than a week to meet tough conditions in exchange for fresh aid.

The ministers want Greek lawmakers to formally approve the measures, which include additional structural spending cuts of 325 million euros for 2012.

They also want a written pledge from coalition leaders that they will implement the reforms, Eurogroup chief Jean-Claude Juncker said. If those conditions are met, the Eurogroup would meet again on Wednesday.