Eurogroup head Jeroen Dijsselbloem on Friday warned Athens to swiftly deliver on overdue reforms as its massive bailout programme fell off track.

"The pressure is back on. We really need some progress. The summer is over, pack up the camping gear," Dijsselbloem, who leads the group of 19 finance ministers from the eurozone, told reporters in Bratislava.

Greece is struggling to deliver on fresh reforms that are needed to unlock a further 2.8 billion euros ($3 billion) in bailout loans and more crucially, launch negotiations on debt relief later in the year.

Athens has committed to deliver on the refroms by the end of the month. They include the long delayed launch of a massive privatisation fund and reforms in the highly sensitive energy sector.

The influential German Finance Minister, Wolfgang Schaeuble, said Greece still had a short period of time to get back in line on its 86 billion euro bailout programme, bitterly agreed in July 2015.

"They have to do this until the end of September, so there is still time for Greece," Schaeuble said.

The eurozone ministers met in the Slovak capital as Greek Prime Minister Alexis Tsipras, an anti-austerity champion, hosted a mini-summit between the European Union's seven Mediterranean states in Athens.

Schaeuble belittled the summit as a political meeting of "socialist party leaders".

"And when socialist party leaders meet, most of the time, nothing intelligent comes out of it," he added.