"If the long-term growth rate declines, together with demographic changes, the natural rate of interest will decline and increase risk for central banks facing a zero lower bound," Kuroda said in a seminar at the World Economic Forum in Davos.

He also said an ageing society could lead to weaker credit demand, pushing financial institutions to take on more risk in search of higher yields and potentially destabilising the financial system.

(Reporting by Leika Kihara, editing by Silvia Aloisi)