Euro zone countries should come up with a timetable to reach full economic union, to reassure investors about the future of the single currency bloc, European Commission President Jose Manuel Barroso said on Tuesday.

Barroso said in a speech that presenting such a roadmap now was important - even if the economic union itself was only to happen much later.

"It is very important, even if you believe that it doesn't come immediately, to define the trend, the objective," Barroso said.

"It is very important also in terms of confidence for the investment in the Euro area now. We will support an ambitious and structural approach which should include a roadmap and a timetable for a full economic and monetary union in the euro area," he said.

European Union leaders asked last week for four highest ranking EU officials, including Barroso, to come up with ideas by the end of June on how a move towards an economic union could be achieved for the euro zone.