PARIS  With the world’s economies moving at two different speeds, fast-growing developing countries are luring money at a pace that, if left unchecked, could set the stage for future problems, the Federal Reserve chairman, Ben S. Bernanke, said Friday.

Mr. Bernanke also defended again the Fed’s steps to bolster economic growth in the United States, this time at a central banking conference here before a meeting of the Group of 20 finance ministers and central bankers. The Fed has kept interest rates low and made money more available to encourage domestic growth even as many other countries have grown increasingly worried about inflationary pressures and taken some steps to curb growth.

China and other emerging markets have blamed the Fed’s strategy for sending waves of capital rushing to their shores, creating a threat of inflation. But Mr. Bernanke said the influx of capital appeared to be driven more by investors’ desire to get a higher return in emerging economies than by the Fed’s policies.

He admonished emerging nations to acknowledge that they have “a strong interest in a continued economic recovery in the advanced economies,” and said they should consider deploying their own tools  including adjusting the level of their currency  to manage their economies and prevent overheating.