The Japanese yen hit two-week highs against the euro and more than one-week highs against the U.S. dollar on Tuesday as traders dialed back expectations of how much new stimulus authorities will inject into Japan's ailing economy.
Most economists surveyed by Reuters expect the Bank of Japan to expand its asset purchases and cut rates further below zero at its two-day meeting that ends on Friday.
The government is also compiling a spending package that some sources have said could be worth up to 20 trillion yen.
Direct fiscal stimulus may be much lower, however, with a Nikkei report on Tuesday citing a figure of around 6 trillion yen over the next few years.
"The market came into yesterday very optimistic both on fiscal and monetary moves," said Steven Englander, global head of foreign exchange strategy at Citigroup in New York. But, "the headlines coming out have thrown a lot of cold water on the view that they are going to do something aggressive."
The yen gained 1.7 percent against the dollar to 103.995, its lowest since July 14, and last traded at 104.59, still down 1.12 percent on the day. The euro fell to 114.465 yen, its lowest since July 12, and last traded at 114.94, still down 1.09 percent.
Comments by Japan's finance minister, Taro Aso, also raised concerns that the government will not work as closely with the BOJ as investors had hoped to implement new stimulus.
"We are also seeing not much pressure from the Japanese government on the BOJ to ease. All this is helping the yen," said Yujiro Goto, currency strategist at Nomura.
The Federal Reserve, meanwhile, is expected to leave interest rates unchanged when it concludes its two-day meeting on Wednesday, though investors will be looking for any signs that the U.S. central bank might be more likely to hike rates in coming months.
Improving economic data has increased expectations that the Fed will raise rates in December, after traders had entirely priced out the possibility of a rate hike this year.
The dollar index, which tracks the currency against a basket of six major rivals, was down 0.16 percent at 97.13.
Sterling also fell after Bank of England policymaker Martin Weale said he had dropped his opposition to policy easing and now favored immediate stimulus.
The pound fell to $1.3131 against the dollar.