"Should the price perspectives, contrary to our expectations, blur in a way that resembles deflation, a programme to buy up current bonds by the ECB would probably mark an appropriate and in my opinion effective reaction," Fitschen was quoted by the weekly Frankfurter Allgemeine Sonntagszeitung as saying.

"Ultimately, only bond purchases weighted with ECB capital holdings would come into consideration," Fitschen said.

The ECB on April 3 opened the door to possibly turning on its money-printing presses to boost the euro zone economy and keep inflation from staying too low.

It kept interest rates steady at 0.25 percent at its regular meeting, but President Mario Draghi said the central bank had unanimously agreed that asset purchases, also known as quantitative easing, might be needed if inflation proved persistently low.

International pressure to act has mounted, most notably from the International Monetary Fund, which has warned of the threat of "lowflation" rather than outright deflation.

(Reporting by Andreas Cremer; Editing by David Holmes)