A list of reforms proposed by Greece last week to help it win creditor support is "far from complete," the head of the Eurogroup said.
Speaking at an event in Amsterdam on Sunday, Jeroen Dijsselbloem, who is also Dutch finance minister, said the Greek proposal was "serious" but not enough.
Dijsselbloem, whose Eurogroup of Eurozone finance ministers will discuss Greece at a meeting today, said Athens had submitted six proposals, with more expected to come.
"The six, those are just the first six. Those absolutely won't be accepted as the 30pc that they wanted to replace," he said. "The Greeks know that too, by the way, they don't have any pretence that this is it."
Dijsselbloem's remarks refer to plans by the new Greek government to replace some of the budget consolidation measures agreed to by the previous government with different reforms.
Once steps to reach these goals are taken, Greece would become eligible for more credit from the Eurozone and the International Monetary Fund, and its banks could again finance themselves at European Central Bank open market operations.
Time is pressing because Greece is expected to run out of cash later this month.
If Greece reaches an agreement on reforms with its creditors it could access €1.8bn of funds remaining from its existing €240bn bailout.