Kazuhito Ikeo, a professor at Keio University in Tokyo, was nominated Thursday to join the Bank of Japan's Policy Board as the government sought to fill one of two positions left vacant since March.

The positions on the nine-member board, including one of Gov. Masaaki Shirakawa's two deputies, have been vacant since the Democratic Party of Japan-led opposition camp used its control of the Upper House to block four candidates in March and April. No one was proposed for deputy Thursday, said Katsuya Ogawa, a DPJ member who was among lawmakers who received the nomination.

Ikeo, 55, has argued that keeping interest rates too low has hampered their use as a policy tool and that borrowing costs will eventually need to rise, said Masaaki Kanno, a former central bank official and now chief economist at JPMorgan Chase & Co. in Tokyo.