Tokyo  - The Bank of Japan's new governor was officially appointed Wednesday, ending the first vacancy in the central bank governorship since World War II.

Masaaki Shirakawa, 58, assumed the post Wednesday evening after both houses of the Diet approved his nomination to succeed former governor Toshihiko Fukui, who ended his five-year tenure on March 19.

The opposition-controlled House of Councillors agreed to promote deputy governor Shirakawa to the governorship of the Bank of Japan after voting down two of the government's previous nominees.

The chamber rejected the nomination of Hiroshi Watanabe as deputy governor because opposition parties feared his past career as a finance minister for international affairs would interfere with the independence of the central bank.

The opposition Democratic Party of Japan also cited previous candidates' backgrounds in the Finance Ministry as reasons for voting down their nominations.

The Democratic Party of Japan also argued that having Watanabe as deputy governor would fall into the practice known as "amakudari," where senior bureaucrats are awarded post-retirement jobs at entities related to the sectors they formerly oversaw.

Prime Minister Yasuo Fukuda's administration argued that such experience would be useful for the leaders of the central bank.

The House of Representatives, controlled by Fukuda's ruling coalition, approved Shirakawa's nomination Wednesday afternoon, just in time for a meeting of finance ministers and central bank chiefs of the Group of Seven leading economies Friday in Washington.

Shirakawa, who is known as a monetary policy theorist, had served at the central bank for 34 years before joining Kyoto University to teach economics in 2006. (dpa)