The Bank of Japan is likely to wait until fall before mulling whether to raise interest rates again after successfully negotiating the tricky task of backing away from its massive stimulus program, according to a former policy board member.

"There must be a tremendous sense of achievement inside the BOJ,” Makoto Sakurai, the former board member, said in an interview Wednesday. "They conquered the mountain and there are no big urgent issues left now.”

Gov. Kazuo Ueda and his fellow board members will likely wait until around the October policy meeting to decide whether the economy can withstand another rate increase, said Sakurai, who remains in touch with incumbent BOJ officials. A steady policy normalization process will probably start next year, with potentially a 25-basis-point rate increase every six months, he said.