Greece appears to be closing in on a new international rescue package despite unresolved doubts among euro zone partners about how fast it will manage to bring its debt down.
Athens set out extra austerity measures on Thursday it hopes will clinch a 130 billion euro ($170 billion) bailout, which will save it from bankruptcy next month, at a meeting of finance ministers from the 17-nation euro zone on Monday.
German Chancellor Angela Merkel, Italian Prime Minister Mario Monti and Greek Prime Minister Lucas Papademos are optimistic that an agreement can be reached on Greece at Monday's Eurogroup meeting, Monti's office said, after the three leaders held a conference call on Friday.
But negotiations with lenders in the European Union and International Monetary Fund are again going down to the wire, straining ties between Greece and northern members of the currency bloc.
"The scepticism is especially strong among the AAA states over whether Greece will be able to make it," Germany's Der Spiegel magazine quoted Austrian Finance Minister Maria Fekter as saying of countries with top-notch credit ratings such as Germany, Finland and the Netherlands.
"The risk of a Greek insolvency is not off the table."
Uncertainty focused on an assessment by the European Commission, the European Central Bank and the IMF predicting Greek debt will be around 129 percent of GDP in 2020, well above a target of 120 percent set in October.
Officials have previously said a target of 125 percent would be acceptable to most euro zone members but further measures will be required to meet even that goal.
Faced with the prospect of a change in the Greek government in April, the euro zone is also seeking greater oversight of the measures Greece is taking to cut its debt, and for the creation of an escrow account to ringfence funds for debt repayment.
Even if Greece secures its second bailout since 2010, officials say there is a growing body of opinion within the euro zone that a new bailout may not solve its problems.
"Honestly speaking, we are thinking about emergency planning if something unexpectedly goes wrong," Dutch Finance Minister Jan Kees de Jager told the Dutch parliament on Thursday.
"It is prudent policy of every finance minister to think about what can happen in addition to the desired path."
The Dutch minister said if a planned meeting of the Eurogroup of finance ministers had gone ahead two days ago, he and his German and Finnish counterparts would have voted against granting Greece more aid.
At that stage, Athens had not yet clarified how it would fill a hole in its 3.3 billion euros of budget cuts this year.
The Greek government eventually produced an extra 325 million euros in cuts along with written commitments from its party leaders that they would stick to the austerity measures, which the euro zone had also made a condition of more help.
"At the instigation of some countries, the Eurogroup meeting was postponed because we thought it would otherwise head for failure," de Jager said. "Otherwise, I, my German colleague and my Finnish colleague could not have gone ahead and would only have been able to say no."
Greece needs the funds before 14.5 billion euros of debt repayments fall due on March 20. As well as mistrust in other European capitals, it faces growing hostility at home.
Tens of thousands protested outside parliament and rioters torched buildings across central Athens as the assembly adopted the package of spending cuts in the early hours of last Monday, and labour unions have called another demonstration for Sunday.
EU officials are still concerned that Greece's overall debt will not fall as projected and believe euro zone finance ministers will need to look at further measures.
Ideas include the euro zone cutting the interest rate on its existing bilateral loans to Greece; increasing the current offer of 130 billion euros of government financing; and asking private investors to agree to bigger losses.
A further option is for the ECB to forego profits on Greek bonds it holds in its portfolio and to re-sell them to the euro zone's bailout fund, the European Financial Stability Facility (EFSF), at the same discount it bought them on the market.
World stocks hit a fresh 6-1/2 month peak on Friday and the euro held above recent lows as hopes Greece will seal a long-awaited bailout deal fuelled risk appetite.
But northern states in the currency union, led by Germany, are particularly doubtful that Greek leaders will stick to the savage cuts in wages, pensions and jobs prescribed by lenders after an election expected in April.
The debt talks have been clouded by growing acrimony between Athens and Berlin, with German Finance Minister Wolfgang Schaeuble likening Greece to a "bottomless pit".
Public Order Minister Christos Papoutsis warned on Thursday that the euro zone approach amounted to "sheer blackmail".
With a go-ahead from Eurogroup ministers, Greece can launch a debt restructuring offer to private creditors aiming to halve the face value of what Greece owes the investors and slashing its debts by 100 billion euros. The real value of bonds held by banks and insurers will fall by about 70 percent.
Euro zone sources said national central banks in the currency bloc would exchange holdings of Greek bonds this weekend in the run-up to the private sector bond swap to avoid taking forced losses - another strong indication that a deal is expected on Monday.
French Prime Minister Francois Fillon cautioned Europe on Friday that it should not "play with the default of Greece".
"The Greeks have promised very important reforms," he told RTL radio. "The Europeans now have to keep their commitments."
Asked if there was a difference of opinion within Germany, Fillon said: "There is no divergence with the Chancellor, who absolutely shares our positions, but we hear people sometimes in Germany express difference opinions ... within the German government."
Greek anger has shifted in recent days from German Chancellor Angela Merkel to Schaeuble, who in Greek eyes appears to have strayed from economic matters into the political, and even electoral process.