Greek Finance Minister Yanis Varoufakishas has warned the country would face a cash crunch within two weeks, and was in an urgent need of the last tranche of rescue funds from its €240 billion bailout.
"The liquidity issue is a terribly urgent issue. It's common knowledge, let's not beat around the bush," Mr Varoufakis said after a meeting with his eurozone counterparts in Brussels.
"From the perspective (of timing), we are talking about the next couple of weeks," he added.
Mr Varoufakis welcomed that the Eurogroup - the finance ministers from the 19 countries that use the euro - issued a positive statement about the talks even though it did not unlock even part of the bailout's final €7.2bn payment.
"What was of the essence was to establish in public the great strides that have been made... and before the liquidity constraints become binding," Mr Varoufakis said.
Short of payout, Greece hopes that the symbolic gesture won Monday will help persuade the European Central Bank to keep emergency funds flowing to Greece's fragile banks.
However, Mr Varoufakis said that decision was up to the ECB.
"The ECB receives no order, from us or the Eurogroup and alone decides when and what it decides it should do," he said.
The minister refused to make much comment on a suggestion by German Finance Minister Wolfgang Schaeuble that Greece could hold a referendum to seek support for further reforms.
"A referendum is always available in order to elicit the support of the Greek people," he said.
"It is a tool available to the Greek government, (but) at the moment it is not on the radar screen."
Eurozone governments have previously opposed such a vote, saying there is no time and it could destabilise financial markets and trigger a run on struggling Greek banks.
When former Prime Minister George Papandreou surprised EU partners by proposing a referendum in 2011 at the height of the euro zone debt crisis, he was summoned to emergency talks with leaders of France and Germany and told bluntly to drop the idea.
With Greece running out of money and desperate for a deal to avert a possible default and exit from the euro zone, Mr Schaeuble said securing public backing for the necessary sacrifices might be useful.
A referendum could make it easier for Greek Prime Minister Alexis Tsipras to climb down on election promises that are making a deal on economic reforms hard to achieve.
"If the Greek government thinks it must hold a referendum, then let it hold a referendum," Mr Schaeuble said on arrival at a meeting of euro zone finance ministers.
"That might even be a helpful measure for the Greek people to decide whether it is ready to accept what is necessary, or whether it wants something different."
Hinting at growing difficulties in persuading conservative German lawmakers to go on funding Greece, Mr Schaeuble said it was unrealistic to think any parliament in Europe would agree without the backing of the International Monetary Fund.
Greece's government has accused the IMF of setting harder targets than the European creditors on pension and labour reforms and a primary fiscal surplus.
The three institutions have denied any internal differences.
Mr Varoufakis, who was due to hold private talks with Mr Schaeuble before the Eurogroup session, told reporters that Athens would make a crucial €750 million payment to the IMF tomorrow as due.
"Greece will always meet its obligations to its creditors and we are obviously going to do that tomorrow again," Mr Varoufakis told Euronews.
