"The efforts of EU countries to identify ways to limit household energy bills are understandable, but indiscriminately increasing expenditure would not be and would not help in the fight against inflation," Rehn said in a statement.

"The long-term debt sustainability of more than one third of the countries in the euro area is under serious threat," he added.

(Reporting by Anne Kauranen; Editing by Balazs Koranyi)