As a formality, the ministers presented their resignation letters to Koizumi during a special cabinet meeting on Monday morning.

Koizumi, who easily prevailed as president of his party in a leadership election on Saturday, is expected to announce a lineup of new cabinet members on Monday with the focus on posts central to his policies on structural reforms, the economy and North Korea.

In early reports, the premier removed controversial Financial Services Minister Heizo Takenaka from his key bank regulator post in the cabinet shake-up, but kept him as economics minister, public broadcaster NHK said.

The fate of Heizo Takenaka, the unelected minister most closely associated with Koizumi's reforms because of his crackdown on the troubled banking system, was being closely watched.

Foreign minister stays

Foreign Minister Yoriko Kawaguchi has hung on to her post,  NHK reported.

Yoriko Kawaguchi (R) will keep her job

Kawaguchi, a former bureaucrat, had come under fire from ruling party heavyweights for her lack of political clout.

Former foreign minister Masahiko Komura, 54, who came last in the four-way LDP leadership election won by Koizumi, had been tipped to regain the job, but has apparently seen his hopes dashed.

Topping the agenda for the foreign minister is the crisis over North Korea's nuclear arms programme and the touchy issue of whether Japan should send troops to help with the reconstruction of Iraq, as well as how much money Tokyo should contribute to rebuild the war-torn country.

Finance hopefuls

The replacement for Masajuro Shiokawa, the 81-year-old finance minister who has said he will quit for health reasons, has also been under scrutiny.

Some have tipped Taro Aso, the 63-year-old former LDP policy chief and economic and fiscal policy minister, for the post. Aso has argued economic growth should come before reforms, while also pushing for land and equity tax reform.

Aso, who served in the short-lived pre-Koizumi cabinet of Yoshiro Mori, had been criticised for not achieving much during his tenure as head of the economic planning agency under former premier Ryutaro Hashimoto.

Trade minister Takeo Hiranuma appeared to rule himself out of a job, by indicating he would not vote for Koizumi.

Koji Omi, 70, former planning agency chief under Hashimoto's second cabinet, was also seen as a candidate for finance minister.

Naoki Inose, a 56-year-old author and member of the premier's highway privatization committee who is not an elected lawmaker, is seen as a candidate for transport minister.

Koizumi has said he will retain right-hand man Yasuo Fukuda, 67, as chief cabinet secretary, the government's top spokesman.

Trade minister Takeo Hiranuma appeared to rule himself out of a job, by indicating he would not vote for Koizumi.