Japan's opposition-led House of Councilors Wednesday approved the government's nomination of Masaaki Shirakawa, acting chief of Bank of Japan (BOJ), as BOJ's governor.

The decision is set to end the three-week leadership vacuum at the central bank as the House of Representatives, where Prime Minister Yasuo Fukuda's ruling bloc commands a majority, is expected to endorse Shirakawa's appointment.

The upper house, however, voted against the candidacy of Hiroshi Watanabe, a former vice finance minister for international affairs, for the post of the central bank's deputy chief at the plenary session.

The main opposition Democratic Party of Japan (DPJ) decided late Tuesday to vote down Watanabe's nomination, arguing that his career background as former senior government finance official would hurt the central bank's independence from the government in monetary policy-making.

The post of the BOJ governor has fallen vacant for the first time in Japan since the end of World War II as the opposition- dominated upper house of the Diet imposed a second veto against the government's nomination of Koji Tanami on March 19 following its rejection of Toshiro Muto a week ago due to the row between the ruling and opposition camps.