Juncker, who is also the European Union's longest serving finance minister, said he had no precise views on the timing of any succession, but it was important the 15 EU nations were able to agree on a single candidate.

Possible replacements whose names have been floated include serving Italian treasury director Mario Draghi; French banker Philippe Lagayette, who lost out in 1998 to Germany's Horst Koehler in the race to head the European Bank for Reconstruction and Development (EBRD); and even serving British Chancellor of the Exchequer Gordon Brown. Brown's aides have described the reports as nonsense. The job has traditionally gone to a European.