Key talks between Athens and its private creditors are set to resume later to try to agree a debt write-off that would dramatically reduce Greece's debt levels.
The two parties have so far failed to agree an interest rate on new bonds that would replace existing debts.
If agreement can be reached, Greece should be in line for additional bailout funds.
Athens has said it hopes to reach a deal by the end of this week.
Charles Dallara, head of the Institute of International Finance (IIF), which is representing Greece's private creditors in negotiations with Athens, is set to resume talks on Thursday afternoon.
He was in Paris on Wednesday to discuss the negotiating position with creditors.
The IIF has said it wants the interest rate on newly-issued bonds to be 4%, while Greece is holding out for a lower rate. Eurozone ministers have backed Athens and called for a rate of less than 3.5%.
Mr Dallara has indicated he is prepared for creditors to write-off 50% of their loans to Greece, as agreed by eurozone leaders in October last year.
Reaching an agreement with private creditors is a precondition of any further bailout funds from the European Union, European Central Bank and International Monetary Fund.
They have indicated that 130bn euros ($169bn; £108bn) is available if a deal can be struck. They are also insisting that Greece accelerates structural reforms to strengthen its economy before any funds are released.
Without the funds, Athens will not be able to make 14.5bn euros of loan repayments that are due in March.
Agreement would also mean Greece's massive debts would be dramatically reduced in one fell swoop, as it would no longer have to repay half of the money it owes to its private creditors.
If a deal is not agreed, Greece could decide itself what, if anything, to repay its creditors.
This so-called disorderly default would undermine confidence in the eurozone economy and its banking system.
Some analysts have said it could result in Greece being forced to give up the euro.