The Bank of Japan it will consider easing its monetary grip further if necessary to attain the target of 2 percent inflation as early as possible, BOJ Deputy Gov. Hirohide Yamaguchi said Thursday.

"It could be the case that further accommodation will be pursued, while examining the situation of economic activity and prices, if necessary," Yamaguchi said in a speech in Nagasaki.

At its policy meeting in January, the BOJ set a 2 percent inflation target to beat deflation. It vowed to start buying around ¥13 trillion in financial assets, including ¥2 trillion in Japanese government bonds every month starting next January without setting a termination date.

Yamaguchi said Japan faces a "window of opportunity" for overcoming deflation.