The European Central Bank on Wednesday further increased the maximum Emergency Liquidity Assistance that Greek banks can obtain by 700 million euros, a banking source said.
The latest move lifts the total ceiling to 71.8 billion euros ($77.3 billion).
Greek banks are dependent on the ECB for financing, but the eurozone's central bank no longer accepts Greek sovereign bonds as collateral for loans.
It had done so previously under a special waiver mechanism, but rescinded that waiver until Athens' new anti-austerity government under Prime Minister Alexis Tsipras can reach a new debt deal with its creditors.
Without the waiver, Greek banks now rely solely on ELA, which is more expensive than normal central bank refinancing operations.
Greek banks have a desperate need for liquidity. From early December to the end of February, individual account holders and business account holders withdrew 25 billion euros on the back of fears about Greece defaulting under Tsipras' radical government.