TOKYO — Asian stock markets climbed in early trading Wednesday, but their gains were modest on growing worries that the U.S. Federal Reserve's stimulus measures may be smaller than expected.

Japan's benchmark Nikkei 225 stock index rose 57.76 points, or 0.6 percent, to 9,435.14. Investors were reluctant to trade heavily ahead of the release of corporate results from major Japanese firms including Sony Corp. and Honda Co. later in the week.

South Korea's Kospi edged up just 0.1 percent to 1,920.52. Shares in Australia, New Zealand and Singapore were higher.

Investors have bet that the U.S central bank will enact a bond-buying program in early November in a bid to support the U.S. economy. Buying bonds would drive interest rates and yields even lower, which makes stocks a more attractive investment.

Traders have speculated the size of the Fed's bond purchase will be around $500 billion. But investors were worrying it may be smaller than previously expected following a speech Monday by William Dudley, the president of the Federal Reserve Bank of New York.

Dudley said further Fed action was "likely to be warranted" unless the economic outlook improved. Still, he added that the Fed "cannot wave a magic wand and make the problems remaining from the preceding period of excess vanish immediately." (AP)