The Bank of Japan is not ready to take additional monetary easing measures soon, despite growing concern over disinflation triggered by a plunge in global crude oil prices, BOJ Deputy Gov. Hiroshi Nakaso implied Monday.

"If falling oil prices lower inflation but inflation expectations remain unaffected and inflation keeps heading toward 2 percent as a trend, there will be no need to respond through monetary policy," Nakaso said in a speech to business leaders in Matsuyama, Ehime Prefecture.

As crude oil prices are likely to rebound moderately ahead, Japan's year-on-year inflation rate is "expected to reach around 2 percent in or around fiscal 2015," said Nakaso, whose policy position is close to that of BOJ Gov. Haruhiko Kuroda, the leader of Japan's unorthodox campaign of "quantitative and qualitative" monetary easing to battle deflation.