Most economists think that the Bank of Japan is getting close to expanding its record monetary stimulus program. What they can't agree on is whether Gov. Haruhiko Kuroda will lead his policy board to take action at a meeting this week, or when they gather again next month.

A majority of 55 percent forecast more easing on July 29, while 27.5 percent project a change as soon as June 16, according to a Bloomberg survey of 40 economists conducted June 6 to 10. When it does adjust policy, increased purchases of exchange-traded funds and a deeper cut to negative interest rates are seen as the two most likely measures.

Just under half expect a boost to the government-bond purchase program that is the core of the current easing program.