European Central Bank policymakers have begun to debate whether interest rates need to be lowered enough to start stimulating the economy, ending years of economic restriction, conversations this week with half a dozen sources indicate.

A faster-than-expected retreat in euro-zone inflation will allow the European Central Bank to cut interest rates again before too long, according to Governing Council member Robert Holzmann.

The governor of the Bank of Portugal, who is also a member of the ECB governing council, said that interest rates could be reduced more boldly if the labor market weakens and inflation trends below target.

WASHINGTON (Reuters) -Euro zone inflation is easing and may fall back to 2% quicker than previously thought, supporting the case for further European Central Bank rate cuts, ECB President Christine Lagarde said on Tuesday.

Olli Rehn, ECB policymaker and governor of the Bank of Finland, speaks to CNBC’s Karen Tso at the IMF Meetings in Washington, D.C.

European Central Bank President Christine Lagarde said, "the direction of travel is clear," on interest rate cuts by the central bank, as she declined to speculate on what it would take for the ECB to deliver a 50-basis-point cut.