Bank of Japan (BoJ) board member Makoto Sakurai said on Friday that the downside risks to the Japanese economy increased in the recent six months. He supported the central bank's monetary policy easing, saying that bold monetary policy measures should be used.

"When you need to take steps, you obviously want to do something effective so you need to take bold steps," he said.

Sakurai also said that new tools were needed to ease the monetary policy further.