German Finance Minister Wolfgang Schauble said Saturday that Greece's latest proposal for a third bailout package from its international creditors is "insufficient."

Schauble gave his assessment upon arriving at an extraordinary meeting of the Eurogroup of euro zone finance ministers, who on Saturday are evaluating Athens' last-ditch proposal aimed at remaining in the 19-nation euro area.

The southern European country is seeking more than 50 billion euros ($56 billion) through 2018 in exchange for carrying out a package of austerity measures it says total some 12 billion euros.

The proposals made by Greek Prime Minister Alexis Tsipras do not allow an "easy outcome," said the German minister, who represents Athens' main creditor, warning of "extremely difficult negotiations" during Saturday's meeting and reiterating that the suggestion of debt relief was off the table because that would violate EU treaties.

Schauble expressed skepticism even though Greece's latest proposal includes several key demands of the Athens' so-called troika of creditors, the European Union, European Central Bank and the International Monetary Fund, including sales-tax hikes and cuts to government spending on pensions.

Many observers said the latest proposal was nearly identical to a European blueprint that Tsipras urged his countrymen to reject in a plebiscite last weekend.

Meanwhile, Germany's Frankfurter Allgemeine Sonntagszeitung newspaper reported Saturday that the German Finance Ministry is planning to propose a temporary five-year Grexit, the common term for a Greek exit from the euro, as a way for Athens to resolve its debt crisis while still remaining in the European Union.

The Greek government's latest proposal includes many concessions for the sake of remaining in the euro zone, Prime Minister Alexis Tsipras acknowledged early Saturday in a speech to parliament, which ratified the package.

Tsipras addressed lawmakers two weeks to the day after he went on Greek television to say that he was turning down a plan of the troika and convening a July 5 referendum on the path forward.

To the surprise of many, more than 61 percent of those who cast ballots last Sunday voted to reject the troika proposal.

The prime minister had said his leftist Syriza party urged the "no" vote to strengthen the government's hand in the negotiations with the creditors and he asserted that the terms of Athens' latest initiative were at least "marginally better" than those available two weeks ago.

His plan, Tsipras said early Saturday, creates "for the first time the possibility to eliminate discussion of the Grexit."

Greece's latest bid also includes a mechanism that would allow Athens to convert some short-term debt into longer-term obligations, which Tsipras sought to portray as a first step toward debt restructuring.

"It is possible to reach a commitment to open a real debate about the debt," the prime minister said.

The Greek government is officially in arrears to the IMF, having missed a payment of 1.5 billion euros ($1.7 billion) that was due on June 30.

Athens found itself unable to make the payment after failing to reach agreement with the troika on the disbursement of the remaining 15.5 billion euros ($17.3 billion) of a second rescue package for Greece.

Syriza won election in January on a promise to throw off troika-mandated austerity that has pushed Greece's unemployment rate above 25 percent even as the ratio of debt to gross domestic product has soared amid an economic contraction of more than 20 percent.