The official said the United States expected big economies to abide by commitments they made in September 2009 at the Group of 20 leaders’ meeting in Pittsburgh, to support the “rebalancing” of the global economy. In practice, that means that export-oriented surplus economies like China, Japan and Germany should foster domestic demand and encourage imports, while debt-burdened deficit countries, like the United States, should trim their trade and budget deficits.

In Japan, after weeks of talking down the yen in what economists called “verbal intervention,” the government finally intervened Sept. 15 in currency markets, the first such maneuver in six years, selling about ¥2.125 trillion to tame the yen’s persistent climb. But a lack of international support has undermined Japanese efforts, and the yen is back to levels seen before the intervention. Meanwhile, some investors have warned that other Asian countries could also try to weaken their currencies as a means of raising exports, setting off a “currency war.”

With intervention yielding little effect, many in the Japanese government have stepped up demands that the Bank of Japan lower rates and buy more government bonds, steps that would put downward pressure on the currency. But Mr. Shirakawa had been reluctant to have the central bank play the role of financing Japan’s public debt, which is fast approaching twice the size of its gross domestic product.

Moreover, future moves by the U.S. Federal Reserve to ease monetary policy further would again reduce the effective interest rate spread between Japan and the United States, limiting the effect of the Bank of Japan’s actions.

The U.S. Federal Reserve has also kept short-term interest rates near zero since December 2008. In the past week, momentum has built toward resuming large-scale purchases of government debt to help the flagging recovery.

The Japanese central bank has long come under fire for failing to end deflation, which has weighed heavily on the economy for 12 years.

Core consumer prices, which had shown signs of stabilizing in 2008, have fallen since early 2009. Consumer prices fell by 0.9 percent in the year to August, according to latest numbers from the Organization for Economic Cooperation and Development.