Greece and international creditors have put final touches to a multi-billion euro bailout accord to keep the country financially afloat and meet an important debt repayment to the European Central Bank within days.

Germany set out "strict" conditions for further aid and said it would be sensible to link the size of the first tranche to Greece's progress in carrying out reforms, a reflection of worry around the euro zone that Athens might not do as promised.

Greek ministers from Prime Minister Alexis Tsipras ruling coalition and representatives of European institutions and the International Monetary Fund resumed talks after a marathon Sunday session that ended in the pre-dawn hours.

A deal for up to £60 billion in fresh loans to the debt-stricken nation must be in place by August 20, when the repayment to the ECB is due. Greek bond yields fell as hopes grew of a speedy end to talks.

An agreement would mark the end of a painful chapter on bailout talks for Greece, which fought against austerity terms demanded by creditors for much of the year before accepting a deal under the threat of being bounced out of the euro zone.

A Greek finance ministry official said: "The two sides have started the final stretch, combing through the final text, sentence by sentence, word by word."

Greek officials had earlier said they hoped to conclude negotiations with creditors by early Tuesday at the latest. The European Commission said it anticipated a deal this month.

"A deal is feasible. A deal can be reached in the month of August, preferably before August 20," European Commission spokeswoman Annika Breidthardt said.

Germany stressed its wish for "quality before speed" in the negotiations, threatening to slow down the process as it pressed for strict conditions to be linked to aid.

Popular misgivings run deep in Germany, the euro zone country that has already contributed most to Greece's two bailouts since 2010, about funnelling yet more money to Athens.

Germany wants a deal that includes an ambitious budget plan, a credible privatisation strategy and a sustainable pension reform by Greece, Finance Ministry spokesman Juerg Weissgerber said.

"It is sensible - that is our belief - to fix the size of the first payment tranche to the extent of the reforms implemented," he said. "That means strict conditionality for financial help."

Mr Weissgerber said Germany was not involved in the negotiations and would need time after any deal to review the results. "We are ready to do this examination quickly this week if necessary, but quality comes before speed," he said.