Japanese Prime Minister Shinzo Abe on Wednesday reshuffled his cabinet with a hefty revamp, aimed at boosting public support while retaining the services of his allies holding similar political views in key ministerial and executive positions.

The reshuffle, which followed a revamp of his Liberal Democratic Party (LDP) executive lineup earlier on Monday, has seen 17 of the prime minister's 19 cabinet ministers either replaced or reassigned within the government, with as many as 13 new ministers being introduced.

Finance minister Taro Aso, who doubles as deputy prime minister, and Chief Cabinet Secretary Yoshihide Suga have retained their positions, as they have served as particularly close allies to the prime minister in their respective posts, held since Abe returned to power in 2012.

In other key moves, foreign minister Taro Kono was picked as defense minister and economic revitalization minister Toshimitsu Motegi was given the foreign minister portfolio.

Motegi, 63, is a Harvard-educated political veteran who worked as a McKinsey consultant before winning a lower house seat in 1993. 

While Kono, who has amused commentators by interacting with people on social media even offering relationship advice at times, struck a hard line during the recent spat with Seoul, which has affected their trade and security ties.

Telegenic Shinjiro Koizumi, the 38-year-old son of much-loved former PM Junichiro Koizumi, was appointed as environment minister.

"Abe intends to start an open race to pick the next prime minister or even the one after that," said SMBC Nikko Securities chief market economist Yoshimasa Maruyama. 

A darling of the Japanese media, Shinjiro Koizumi received blanket coverage for his recent marriage to television broadcaster Christel Takigawa, which was announced at the prime minister's office. 

He is the third-youngest minister appointed to the Cabinet in Japan since the end of World War II, in a country when seniority is prized in politics and many other walks of life. 

Despite intense media spotlight, he has been coy on expressing his view on the issues of the day and there will be close scrutiny over his policies on nuclear power, particularly on whether he will break with his father's anti-nuclear stance. 

In other moves aimed at shoring up support among his administration, Koichi Hagiuda, executive acting secretary-general of the LDP was named education minister, while Deputy Chief Cabinet Secretary Yasutoshi Nishimura will now assume the position of economic revitalization minister.

Abe named upper house lawmaker Seiko Hashimoto as the minister in charge of the 2020 Tokyo Olympics and Paralympics, bringing the number of females in his cabinet to two. From the LDP's coalition Komeito ally, Kazuyoshi Akaba has replaced Keiichi Ishii as minister of land, infrastructure, transport and tourism.

Abe is set to become Japan's longest-serving prime minister in November but is expected to step down at the Liberal Democratic Party (LDP) leadership election in 2021, and the jostling for the position is already beginning. 

China appreciates Kono's for his great contribution to improving China-Japan relations, said Chinese Foreign Ministry spokesperson Hua Chunying when learning of reshuffle on Wednesday. "We hope that he would continue to play an active role in the bilateral cooperation," Hua added.

Meanwhile, Hua also congratulated Motegi for being Japan's new foreign minister. "We hope that both parties would work jointly to implement the important consensus reached by two leaders and push forward China-Japan relations in the new era," said Hua.

(With input from Xinhua, AFP)