A Grexit might be the would be the "worst of catastrophes" for Greece, but it will be no drama for the euro, according to France's finance minister.

Speaking on French radio, Finance Minister Michel Sapin said: "It would be no drama for us to see Greece leaving the euro. It would not be serious from a financial or economic point of view."

Greece has until the end of June to pay back to the International Monetary Fund about €1.6bn (£1.18bn, $1.8bn) in loans. It has also to agree to stiff terms with its creditors – including pension cuts, public sector redundancies and a VAT increase – to receive €7.2bn in a cash-for-reforms loan to avoid bankruptcy and a default.

To illustrate Athens's dire straits, Greek Prime Minister Alexis Tsipras has somehow to find €7.8bn to pay pensions and public sector wages over the next two months. And Athens has to pay back a further €5.4bn in loans by the end of July.

Sapin added: "From here to the end of June there is an agreement between Greece and its European partners, beyond the end of June, there is no agreement." A Grexit, he said, would be the "worst of catastrophes" for Athens.

The French Finance Minister's comments came as senior Greek negotiators arrived in Brussels to continue negotiations. In Berlin, Wolfgang Schäuble, the German Finance Minister, and Yanis Varoufakis, his Greek counterpart, at the same time held private talks in Berlin.

Tsipras has angered former allies

Schäuble has been scathing of the Greek government's tactics, especially after Tsipras last week presented a counter-proposal to what he called the creditors' "absurd" bailout plan.

"You have to act sensibly, that is what makes the current talks with Greece so tiring," Schäuble said. "[Greece's ruling radical] Syriza succeeded in talking Greeks into believing there is a simpler way to stay in the euro, a way without major reform efforts. Perhaps they shouldn't have made promises like that."

Tsipras has found himself in hot water with the European Commission president, Jean-Claude Juncker, normally an ally.

Juncker accused Tsipras of lying about a draft agreement drawn up Germany, France, the IMF, the commission and the European Central Bank, saying he had misled the Greek public over the intentions of the eurozone and failing to meet negotiating deadlines.

"I can only warn the Greek government against turning down the hand held out to them," said Martin Schulz, the German Speaker of the European Parliament, another former Tsipras ally. "Time is running out and the consequences would be dramatic."