A third of the nine members of the Bank of Japan's Policy Board were skeptical at their meeting last month about achieving the BOJ's 2 percent inflation goal in the targeted period, the central bank's minutes showed on Monday.

"One member expressed the recognition that it was rather unlikely that the 2 percent target would be achieved in a sustainable manner, given that the year-on-year rate of increase in the CPI (all items less food and energy) had recently been in the range of 0.0-0.5 percent despite the yen's depreciation," according to the minutes for the Jan. 20-21 meeting.

At the meeting, the BOJ lowered its inflation forecast for fiscal 2015 starting in April to 1.0 percent from its previous outlook of 1.7 percent. For fiscal 2016, the outlook was raised to 2.2 percent from 2.1 percent.

The member said the outlook for price increases "would likely be substantially below the median of the Policy Board members' forecasts" through fiscal 2016, the minutes showed.

At a press conference held after the meeting, Gov. Haruhiko Kuroda said the bank would be able to meet the goal in or around fiscal 2015 as initially sought.

A different member noted that expectations for price rises were weakening, the minutes said.

But many members agreed that the outlook for the underlying trend in prices was unchanged. Given the current uncertain outlook for crude oil prices, the timing for reaching the 2 percent target "could be either earlier or later to some extent," the minutes reported.