A Bank of Japan policymaker warned Thursday that the central bank's decision last October to ease monetary policy further would increase the risk of undermining economic and price stability in the long term.

Takahide Kiuchi, one of four Policy Board members who opposed the central bank's additional monetary easing, said his decision reflected his concern that the side effects would "outweigh the positive effects."

"This would heighten the risk of undermining economic and price stability in the long run," he said in a speech in Maebashi. "I judged that the accompanying positive effects would not be worth the costs and side effects."