Former Eurogroup president Jean-Claude Juncker says mistakes were made in the bailout of Greece.

The Luxembourg Prime Minister, who played a central role in the 2010 bailout out through his role as the head of the grouping of the euro finance ministers, said the European Union and the International Monetary Fund were "overly optimistic" in the early stages of the bailout process.

Juncker stepped down as the Eurogroup president earlier this year.

His remarks during a visit to Athens Tuesday follows on from last week's admission from the IMF that the Greek rescue deal had failed to restructure the country's national debt early enough. A spat has since developed between the EU and the IMF.

Juncker, who met with Greek Prime Minister Antonis Samaras, was awarded Greece's highest honor.