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.

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.

LISBON (Reuters) - Inflation in the euro zone has slowed to converge with the European Central Bank's 2% target and the risk now is undershooting the goal, which could stifle growth, ECB policymaker Mario Centeno told an event in Washington on Tuesday.

The ECB cut rates three times already this year from a record high and markets now see cuts at each of its next four or five meetings as growth is flatlining around zero and inflation is lower than forecast.

Top officials at the European Central Bank said they may accelerate the pace of rate cuts in coming meetings as the outlook for the eurozone economy darkens.

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.

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.

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.