Greece's main parties on Monday jointly called for an agreement with EU-IMF creditors to restore liquidity to struggling banks and address the viability of the country's enormous debt, the president's office said.

"The restoration of liquidity to the credit system through an understanding with the European Central Bank is a top priority," it said in a statement.

The call came after Greece's conservative, socialist, pro-EU and nationalist parties held a seven-hour meeting with Prime Minister Alexis Tsipras.

The parties also insisted that the broad 'No' vote in Sunday's referendum did not signify a popular Greek desire to leave the eurozone, and they called for "reliable reforms...with as little austerity consequences as possible."

"The recent verdict of the Greek people is not a mandate for rupture, but a mandate to continue and strengthen the effort to reach a socially fair and economically viable deal," the parties said in the statement.

Defence Minister Panos Kammenos -- whose nationalist ANEL party is in coalition with the ruling Syriza party -- said as he left the meeting that Greece had "no option" but to reach a deal.

"There is no other option but a deal," Kammenos told reporters, adding that the joint statement was designed to give "strength to the prime minister to go to Brussels tomorrow and negotiate on behalf of the Greek people".

Eurozone leaders are to hold an emergency summit on Tuesday, and several of them had described the referendum vote as an in-out decision on Greece's euro membership.

Eurogroup chief Jeroen Dijsselbloem said Monday the result of the referendum had brought Europe "no closer to a solution" to Athens' financial situation.

"If anything, the fact that suggestions were turned down, makes it even more difficult," Dijsselbloem, who is also the Dutch finance minister, told journalists in The Hague.