The policy-setting panel of the Bank of Japan voted unanimously last month to keep intact its easy monetary policy, saying its effects are beginning to be observed, according to the minutes of its May 17-18 meeting released Wednesday.

The BOJ's Policy Board members agreed that "the effects of the monetary easing measures are starting to be observed in financial markets," the minutes say.

The panel also agreed that "the economy has on the whole continued to be in line with expectations," according to the minutes. "All members therefore agreed that the bank should maintain the current guideline for market operations."

The current guideline refers to the BOJ's decision on March 19 to effectively reinstate a "near-zero-interest" rate policy.

The board members also agreed to closely monitor both the extent to which the monetary easing measures permeates the economy and developments in the U.S. economy, the minutes say.