One French source said the idea, floated by Germany, was for funds from a planned second 130 billion euro bailout program for Greece to be siphoned off to reassure bondholders that future payments were guaranteed.

The scheme, which was only at a preliminary stage, was to demonstrate that debt payments were being given priority in Greece's budget, the French source said.

Greece, which has repeatedly failed to meet fiscal targets set out by its international lenders, had reacted angrily to German calls for the appointment of a "budget commissioner," saying it would be undermine national sovereignty.