"Solidarity in our Union is alive. Grexit is dead," Samaras added as he went into talks with EU conservative parties ahead of a two European Union summit kicking off later in the day.

Much-needed cash to keep Athens afloat that was released by eurozone finance ministers had been blocked since June over concerns that recession-hit Greece was not sticking to economic reform vows, and might not be abe to pay back its debt.

"Today is not only a new day for Greece, it is indeed a new day for Europe," Samaras said.

The rescue funds for Athens "will be flowing to Greece as early as next week," the head of the Eurogroup Jean-Claude Juncker said after ministers of the 17-nation eurozone agreed to release a first 34.3 billion euros of aid.

The funds will go to help recapitalise Greece's banks and cover the costs of a debt buy-back, with some left over for the state budget. Another 14.8 billion euros will be available in the first quarter.

"Together with Greece we are prepared to take additional measures if necessary ... (so as) to put Greece on a path to debt sustainability," Juncker said.

The EU's Economic Affairs Commissioner Olli Rehn said the European Union was "well aware of how difficult the situation is for the Greek people."

There were "no easy solutions" and "reforms are difficult", he added.

"Now it will be essential to maintain the momentum of reform," he added. "Much has been achieved but much remains to be done."