European Central Bank (ECB) Executive Board member Peter Praet said in a speech on Thursday that the central bank's monetary policy adopted since June 2014 was effective.

"It has led to a substantial easing of financial conditions, and this has in turn led to an improvement in both output and inflation relative to counterfactual scenarios," he noted, adding that higher structural growth and employment could not depend on monetary policy.

Praet pointed out that the ECB could add further stimulus measures if the downside risks increase.

"If further adverse shocks were to materialise, our measures could be recalibrated once more commensurate with the strength of the headwind, also taking into account possible side-effects," he said.

Praet noted that the central bank did not discussed helicopter money.