PARIS--Low and declining inflation remains the main challenge in Europe, European Central Bank governing council member Christian Noyer said Tuesday.

"This prevents adjustments in relative prices, an important mechanism to eliminate gaps in competitiveness, and increases the risk of outright deflation, should a negative shock occur in the future," Mr. Noyer said at a conference in Paris.

The European Central Bank is "ready to take any actions that may prove necessary should downside risks further materialise," he added.

Mr. Noyer's comments echo those of ECB President Mario Draghi, who kept the door open to additional stimulus including large-scale asset purchases if needed to fight excessively low inflation, while rejecting concerns over super-easy monetary policies at the ECB and other central banks.

Write to Noemie Bisserbe at noemie.bisserbe@wsj.com

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