Reuters reports that ECB policymaker Francois Villeroy de Galhau said that the amount of monetary stimulus is not the only question facing the European Central Bank and it also needs to look at how it is transmitted to the economy.

"In the face of prolonged uncertainty, out first objective must be keeping very favourable financing conditions as long as necessary," Villeroy said.

"To this end, the recalibration of instruments must focus in particular not only on the level of monetary support, but also on the duration, flexibility and efficient targeting, in short, the quality of monetary policy transmission," he added.