Among the changes in Mr. Kan's third cabinet since becoming prime minister were new fiscal policy, trade, justice and transport ministers, but the premier kept other key posts such as foreign, finance and defence portfolios unchanged.

In doing so Mr. Kan has bowed to pressure from the conservative opposition in order to help secure the passage of bills to finance the 2011 budget, as he seeks to energise an economy mired in deflation, saddled by huge debt and burdened by a greying population.

Mr. Kan appointed 72-year-old conservative former finance minister, fiscal hawk Kaoru Yosano, as his new fiscal policy minister, also putting him in charge of tax and social welfare.

His brief will be to help balance state finances in Japan, where the public debt is now twice the size of the $5 trillion economy, and where the rapid ageing of the population will put more pressure on the public purse.

Mr. Kan replaced his trade minister, Akihiro Ohata, who has been reluctant to support the premier's initiative to join the US-backed Trans-Pacific Partnership being debated by nine countries.

Ohata will be replaced by Banri Kaieda, who previously served as fiscal policy minister. Satsuki Eda takes on the role of Justice Minister.

The two, Sengoku and the Land, Infrastructure, Transport and Tourism Minister Sumio Mabuchi, left the cabinet. Former trade minister Ohata stayed on to replace Mabuchi.