German Chancellor Angela Merkel agreed in a phone call with French President Francois Hollande last night that a euro zone leaders' summit should be held tomorrow , a German government spokesman said.

The chancellor and president also agreed that the referendum result should be respected, said the spokesman.

German Foreign Minister Frank-Walter Steinmeier said the outcome of Greece's referendum had to be accepted, and that the ball was now in the Greeks' court.

'First of all we have to accept such a result,' Steinmeier told reporters as he arrived in Vienna to join the Iran nuclear talks.

'Which (conclusions) are now to be drawn, this is a decision which first and foremost must be made in Greece and that's why the ball is now in Athens' court.'

Senior German conservative Michael Fuchs told Reuters yesterday that Greek Prime Minister Alexis Tsipras had caused a “disaster” after referendum results showed the country has rejected eurozone bailout terms.

“I very much regret the result,” Fuchs said by telephone.

“Tsipras has caused a disaster and must see how to pick up the pieces. There is no chance that a solution will be achieved within 48 hours,” said Fuchs, who has reservations about Greek bailouts.

Greece's finance minister Yanis Varoufakis said a 'No' vote from Greeks to a bailout package from lenders on Sunday was a vote in favour of democracy and social justice that allowed Athens to call on its partners to find a fair deal. “As of tommorrow, with this brave 'No' the Greek people handed us.... we will extend a helping hand towards our lenders. We will call on each one of them to find common ground,” Varoufakis told reporters.

“As of tomorrow, Europe, whose heart is beating in Greece tonight, is starting to heal its wounds, our wounds. Today's No is a big Yes to democratic Europe.”

Meanwhile, Greeks cannot withdraw cash left in safe deposit boxes at Greek banks as long as capital restrictions remain in place, a deputy finance minister told Greek television yesterday.

Greece’s government shut banks and imposed capital controls a week ago.

Deputy Finance Minister Nadia Valavani told Alpha TV that, as part of those measures, the government and banks had agreed at the time that people would also not be allowed to withdraw cash from safe deposit boxes.

Greece’s government is not considering printing a new currency, a government official said yesterday. “We are not discussing a parallel currency,” he said.