The Abe administration should proceed with the next consumption tax hike as planned to signal it is serious about reining in the world's biggest debt burden, an adviser to Bank of Japan Gov. Haruhiko Kuroda said.

Annualized growth of 2.5 percent or more this quarter would be a green light for Prime Minister Shinzo Abe to go ahead with the increase, supporting the economy with additional stimulus as needed, Masahiro Kawai, a professor at the University of Tokyo, said in an interview Wednesday.

Abe is to decide by the end of the year whether to raise the levy by another 2 points to 10 percent after the rise to 8 percent in April caused the worst contraction in more than five years.