Cash-strapped Greece has managed to make a €200 million repayment to the International Monetary Fund, as its long-stalled bailout negotiations appeared to make some progress.

The country has a much larger repayment due next week that it will struggle to manage. On May 12, Greece must repay about €770 million to the IMF - and it is not clear whether it will be able to meet both that payment and pay some pensions and salaries due mid-month.

Greece once more faces the possibility of defaulting on its debts in the next few weeks, which could set off a chain reaction that jeopardises its membership in Europe's joint currency.

The country's left-wing government has been locked in negotiations with its creditors and the institutions overseeing its bailout - the IMF, European Central Bank and European Commission - for the past three months over reforms required to unlock the remaining €7.2 billion installment of its €240 billion bailout.

With no other significant external source of funding, Greece will not be able to continue meeting its debt repayments and pay for day-to-day spending without the rescue loans.

In Brussels, technical talks that started last week were extended beyond today amid hopes for a breakthrough. A eurozone official confirmed there is now visible progress after the talks had been bogged down for weeks.

Greek prime minister Alexis Tsipras spoke by phone with European Commission President Jean-Claude Juncker today, and both said that "constructive talks should continue".

They issued a joint statement saying the two discussed "progress made in the talks... over the last few days" and spoke of details of the reforms Greece needs to implement.

According to the statement, those include modernising the pension system "so that it is fair, fiscally sustainable and effective in averting old-age poverty". They also discussed "the need for wage developments and labour market institutions to be supportive of job creation, competitiveness and social cohesion".

Finance minister Yanis Varoufakis was in Rome to discuss the issue with his Italian counterpart Pier Carlo Padoan, before heading to Madrid on Friday to meet his peer Luis de Guindos.

Both sides hope to make progress by May 11, when eurozone finance ministers are due to meet. But expectations of a deal being reached by then have faded.