Bank of Japan Deputy Gov. Masazumi Wakatabe said Wednesday the central bank should not hesitate to ramp up stimulus if risks to the economy threaten the achievement of its inflation target.

Wakatabe, a vocal advocate of aggressive monetary easing, also said the demerits of the BOJ's ultraloose policy have yet to outweigh the benefits, rebuffing calls for the central bank to whittle down its radical stimulus program.

"If necessary, the BOJ should ease policy further without hesitation," Wakatabe said at a news conference after meeting business leaders in the city of Niigata.