The Bank of Japan has failed to end more than a decade of deflation by being too cautious, according to Takatoshi Ito, a former Finance Ministry official who is a contender to become the central bank's next governor.

The BOJ Policy Board under Gov. Masaaki Shirakawa, who will step down in April, has done "too little, too late," Ito, dean of the University of Tokyo's Graduate School of Public Policy, said Thursday in Tokyo.

The BOJ should have started its asset purchase program earlier, and it has been "extremely passive in building inflation expectations," he said.