Prime Minister Yoshihiko Noda says his partially reshuffled Cabinet is the best lineup ever, but it will need to be to face the turbulence expected in the Diet session that started Tuesday.

Noda's most challenging task will be the push by his Democratic Party of Japan-led government to pass social security reform and double the 5 percent consumption tax in a Diet in which an uncooperative opposition camp controls the Upper House and strong voices continue within the DPJ against raising the sales levy.

Noda told the DPJ's annual convention a week ago he "will pursue the reforms at any cost."