Prime Minister Alexis Tsipras is facing open revolt from some of his own ministers as he seeks support for a bailout deal that, while saving the country from financial collapse, will cause years of more pain for Greeks.
The government must pass a raft of measures through Parliament by Wednesday night, including consumer tax increases and pension reforms, in order to start negotiations with European creditors on a third bailout worth as much as 85bn euros ($95 bn).
Tsipras battled to hold his ruling Syriza party together as opposition mounted to a shocking new bailout deal that requires Athens to push through tough reforms within two days.
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With around 30 hardline Syriza lawmakers threatening to oppose the latest tough reforms demanded by Greece's international creditors, Tsipras faced the unenviable task of turning to pro-austerity opposition parties to push the deal through parliament by Wednesday.
In the agreement struck on Monday with the eurozone to prevent Greece crashing out of the euro, the Greek parliament must pass sweeping changes to labour laws, pensions, VAT and taxes.
Only then will the 18 other eurozone leaders start negotiations over what Greece is to get in return: a three-year bailout worth up to 86 billion euros ($96 billion), its third rescue programme in five years.
With much of the party up in arms, Tsipras loyalists were hard at work on Tuesday to convince a sceptical party that the tough cuts could be softened through alternative measures.
"I believe the people trust Tsipras and the government to remove these measures in the implementation phase, there can be policies that can cancel them out," said Interior Minister Nikos Voutsis. But a number of prominent leftists were refusing to budge.
Syriza's junior coalition partner, the nationalist Independent Greeks party (ANEL) also said it would not approve the tough measures but would stay in the government.
Tsipras has predicted "the great majority of Greek people will support" the deal, which he said includes help to ease Greece's huge burden of debt and revive its crippled banking system.
The prime minister said he took responsibility for a tough bailout deal clinched with the eurozone to save the near-insolvent country, despite not believing in many of the draconian reforms it demands.
"I assume responsibility for all mistakes I may have made, I assume responsibility for a text I do not believe in, but which I signed to avoid disaster for the country, the collapse of the banks," he said in an interview
on Greek public television on the eve of a key parliament vote on the reforms.
'May pass with votes, but will never pass the people'
Many ordinary Greeks, however, are sceptical that the deal will bring about any improvement in their lives. Some expressed their anger on social media, where the Twitter hashtag #ThisIsACoup trended.
Greece's public servants are also to stage a 24-hour strike on Wednesday, the first big stoppage since Tsipras took power.
Faced with a eurozone deeply distrustful of Athens after five months of tense meetings, the 40-year-old Tsipras had to agree to demands that critics say rob Greece of financial independence.
"This agreement may pass with (opposition party) votes, but it will never pass the people," the head of a hardline Syriza faction, Energy Minister Panagiotis Lafazanis, said.
If Greece passes it, Europe's next step would be to push the deal through several national parliaments, many in countries that are loath to afford Athens more help.
Germany's Bundestag is likely to vote on Friday, provided the Greek parliament rushes through the four new market-oriented laws by Wednesday.
Despite strong opposition, Tsipras also yielded to a plan to park assets for privatisation worth up to 50 bn euros in a special fund.
Some 25 billion euros of the money in that fund will then be used to recapitalise Greece's cash-starved banks.
There is also a pledge to reverse laws brought in by the Syriza government that run counter to Greece's earlier bailout arrangements in 2010 and 2012.