Central bankers from Japan and the U.K. predicted their new campaigns to encourage expansion will work, sustaining support for global growth even as the Federal Reserve considers a reduction in stimulus.

As the annual gathering of central bankers and economists in Jackson Hole, Wyoming, drew to a close on Saturday, Bank of Japan Gov. Haruhiko Kuroda said his souped-up asset-buying "has started to exert effects" on the world's third-largest economy.

Bank of England Deputy Gov. Charlie Bean said the U.K.'s pledge this month to avoid raising interest rates before unemployment falls to 7 percent should restrain U.K. gilt yields and boost confidence among consumers and companies.