A top government official said Prime Minister Shinzo Abe should delay a planned consumption tax increase, the strongest sign yet that economic weakness is causing concern among those close to Abe ahead of his final decision on the levy.

"I think it should be delayed" by 1½ years to April 2017, the prominent official told a small group of people in a recent conversation on condition of anonymity. He expressed concern that raising the national sales tax too soon after a damaging hike in April could derail an economic recovery.

Powerful interests like the Finance Ministry, the Bank of Japan and major companies want Abe to raise the tax as planned in October 2015 to keep Japan's pledge to reduce the biggest debt burden in the developed world. But the economic and political environment is making it harder for Abe to make unpopular policy choices.