Glenn Hubbard, former chairman of the U.S. Council of Economic Advisers, said the Bank of Japan should exercise caution when ending its ultraeasy monetary policy because inflation is barely existent.

"Inflation is still modest. It's about half a percent in the last forecast," Hubbard said. "That's, to me, still dangerously low."

Hubbard made the comments in an interview in Tokyo with the media Tuesday, a day before the BOJ began its two-day Policy Board meeting.