“After what I've heard of the technical conversations over the weekend, I'm very sceptical”, Schäuble said in response to a question on Deutschlandfunk radio.
Finance ministers from across the Eurozone will meet in Brussels at 3 pm to try and hammer out a deal with the Greeks.
Current bailout arrangements for the country run out at the end of February, meaning that it risks bankruptcy unless it can reach agreement on a new financial aid programme with its European neighbours.
But several of those countries – including Germany - require that any agreement with Greece be approved by their own parliaments, leaving the time available to reach a compromise even shorter.
The picture is complicated further by the apparent disunity between Greek finance minister Yanis Varoufakis and his Prime Minister, Alexis Tspiras.
Varoufakis, himself not a member of Syriza, appeared ready to make a deal on Thursday, but rejected the other countries' offer after speaking with Tsipras at the last minute.
A Greek government spokesman said on Sunday that the country would reject any further social cuts and accept no deal with “the properties of earlier aid programmes”.
That goes directly against the preferred solution in Berlin and Brussels, which would see the current arrangement extended for six months and an additional €7.2 billion sent to Athens.
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