"Our model gives a 10 to 20 percent probability to inflation turning negative (in the euro zone)," Olivier Blanchard told reporters on a conference call, adding that the IMF still sees positive price growth in its baseline forecasts.

He called on the European Central Bank to do all it can to anchor price expectations and boost demand in the euro currency bloc, where southern countries like Portugal and Greece continue to face weak demand.

(Reporting by Anna Yukhananov; Editing by Paul Simao)