Tokyo: Japan's sixth new leader in five years on Friday named a youthful Cabinet lacking the usual political heavyweights, as he attempts to unite a divided party and safeguard a fragile post-quake recovery.

Prime Minister Yoshihiko Noda gave the key posts of Foreign and Finance Ministers to lawmakers in their 40s, considered young in Japanese politics for such roles.

The position of Finance Minister went to relative unknown Jun Azumi, 49, against expectations Noda would pick a veteran from his ruling Democratic Party of Japan (DPJ). Koichiro Gemba, 47, becomes Foreign Minister.

The new Cabinet, unveiled by new Chief Cabinet Secretary Osamu Fujimura, was expected to be sworn in by Emperor Akihito later on Friday.

"The appointments were aimed at achieving party unity," Fujimura told a press conference, adding that the new government's priority was recovery from the March 11 disaster and resolution of the ongoing Fukushima nuclear crisis.

Azumi, a native of the northeastern prefecture of Miyagi devastated by the March earthquake and tsunami, worked as a reporter for NHK before launching his political career. This is his first role as a Cabinet minister.

He was the ruling party's chief of Parliamentary Affairs under outgoing leader Naoto Kan, and used his firm ties with the opposition in a hard-fought campaign to win cooperation in passing key bills through a divided Parliament.

As Finance Minister, Azumi faces the tough tasks of shielding the economy from a strong yen and addressing a ballooning public debt as the nation's rapidly ageing population increases social security costs.

Gemba, the new Foreign Minister, was State Minister in charge of national policy in the outgoing cabinet. Japanese diplomacy was heavily tested last year by territorial disputes with China and Russia.

The new Foreign Minister must also work to maintain relations with key ally the United States against a backdrop of protracted discussions over the relocation of a US military base on the southern island of Okinawa.

The defence portfolio was given to 69-year-old Yasuo Ichikawa while Yoshio Hachiro, 63, was named Minister of Economy, Trade and Industry.