Greek Prime Minister Alexis Tsipras urged parliament early Saturday to approve a reform package offered to the country's creditors, to keep the nation 'alive' and in the European Union.
His call for a vote of "national responsibility" came as an EU source in Brussels said the country's latest debt proposals were "positive" enough to form the basis of a massive new bailout worth 74 billion euros ($82 billion).
Tsipras spoke as parliament prepared to vote on his controversial package of reforms, which have sparked criticism from hardline members of his radical left ruling party Syriza.
Most opposition parties however have expressed willingness to back them.
"It is a choice of high national responsibility, we have a national duty to keep our people alive...we will succeed not only to stay in Europe but to live as equal peers with dignity and pride," Tsipras said.
His government is asking Greece's international creditors for a three-year funding plan including debt relief and a separate 35-billion-euro investment package.
Despite growing anger in Greece over austerity, Tsipras caved in to demands by the creditors for a pension overhaul, tax hikes and privatisations.
- A 'positive' evaluation -
The concessions have brought relief from many quarters. In Brussels, an EU source who asked not to be named said "there has been positive evaluation of the Greek programme."
The EU's bailout fund, the European Stability Mechanism, was ready to consider putting up 58 billion euros plus 16 billion euros from the International Monetary Fund for what would be a third debt rescue, the source said.
This would now go to the Eurogroup of 19 eurozone finance ministers who meet Saturday but it stood only a "50-50" chance of approval due to opposition by hardliners such as Germany who oppose any debt relief for Athens.
The Greek proposals fail to meet international demands on some thorny issues, including tax breaks for Greece's islands and cuts to military spending.
Speaking ahead of an EU summit called Sunday for a final decision, Tsipras admitted mistakes had been made but insisted the new proposals were the best possible deal for Greece.
- Debt mountain -
"The loan deal...entails many proposals that are far from our pledges, from what we feel is right for the recovery of the economy," the prime minister said.
But it was "marginally better" than proposals put forward by the creditors last month that did not offer debt relief from Greece's suffocating 320-billion-euro ($350-billion) mountain of debt.
Finance Minister Euclid Tsakalotos said the government wanted parliament's approval "to strengthen the country's bargaining position, to achieve better terms in the agreement."
But the Greek leader also risks alienating large numbers of the ruling party's supporters, who rejected in a national referendum last Sunday a very similar set of proposals put forward by Greece's creditors.
Some 8,000 people gathered in Athens ahead of the parliamentary vote to protest against more austerity, police said.
In a bid to head off a possible challenge to the measures within his hard-left party Syriza, Tsipras urged lawmakers "to stand united and firm in front of these important decisions."
- Euro, markets soar -
Earlier, France and Italy welcomed the new proposals, with French President Francois Hollande calling them "serious and credible" while cautioning that "nothing is decided yet."
Italian Prime Minister Matteo Renzi declared himself "more optimistic" that a deal would be done.
But Germany said the outcome of this weekend's crisis talks was "completely open."
Berlin leads a bloc of hardline eurozone nations saying that, after two bailouts over the past five years totalling 240 billion euros, and 107 billion euros in debt forgiveness in 2012, Greece is looking like bottomless money pit.
The possibility of a breakthrough sent stock markets soaring in Europe, Asia and the US on Friday.
Meanwhile the euro briefly rose above $1.12 for the first time in July before falling back slightly in later trade, still up at $1.1152.
Although Greek voters last Sunday roundly voted "No" to accepting tough austerity terms for a bailout that expired June 30, they are alarmed at capital controls that have closed banks and rationed ATM cash.
They also overwhelmingly want to keep the euro.
"The government has to find a deal with its European partners no matter what. We didn't vote 'No' to leave the eurozone," said a pensioner in Athens, Nikos Eftekidis.
But another pensioner, Giorgos, said the "government's proposed measures are very tough, I wasn't expecting that. That's not what the Greeks voted for."