TOKYO (THE WASHINGTON POST) - Japanese Prime Minister Shinzo Abe on Thursday (Aug 3) praised the man who might one day take his job.

Mr Abe appointed Mr Fumio Kishida as chairman of his Liberal Democratic Party's (LDP) Policy Research Council, part of a wider reshuffle of his ministers and party officials after a slump in popularity and a humiliating local election defeat.

The move frees up Mr Kishida to challenge Mr Abe in an election for party president expected in September in 2018.

Mr Abe's struggles have increased tensions between the LDP's factions, one of which is headed by Mr Kishida.

Kyodo had reported in July that Mr Kishida asked to leave the Cabinet.

"Mr Kishida achieved great things as foreign minister," Mr Abe told reporters later. "He is someone who will absolutely play a central role in the future of Japan, so now I have expectations of him taking responsibility for the whole range of party policy."

Allegations of cronyism have undermined public trust in Mr Abe, while a series of scandals and gaffes have focused criticism on his ministers. His falling support does not necessarily put his job in immediate danger, though a recent poll indicated that voters no longer see him as the most appropriate person to lead the government.

"Various problems were pointed out in the last session of parliament, which sparked a great deal of suspicion from the people," Mr Abe told reporters. "I want to reflect deeply on that and apologise to the people," he added, bowing at length in front of the cameras.

Mr Abe's woes come as his government faces several offshore problems: North Korea has tested two intercontinental ballistic missiles within a matter of weeks, despite international sanctions against the regime, and Japan must navigate the economic protectionism of US President Donald Trump's administration.

Until recently thought to be guaranteed a third straight term as party leader, Mr Abe suddenly will have to fight off rivals to stay in power. He vowed to focus on growing the economy in a bid to restore confidence in his leadership.

Speaking to reporters after the change was announced, Mr Kishida on Thursday focused on policy issues, including how to bolster the economy.

Having served as Mr Abe's foreign minister since 2012, Mr Kishida is not known for expertise on the economy. Nevertheless, with the LDP divided over how to tackle Japan's ballooning debt and the best path for monetary policy, a leadership battle would raise doubts among investors.

While Japan's economy is heading for a sixth-straight quarter of growth, and unemployment is at its lowest levels since the 1990s, inflation has stalled at 0.4 per cent - far from the central bank's 2 per cent target.

Mr Kishida is seen as less hawkish than Mr Abe on defence, telling reporters on Thursday that his caution on changing the pacifist Article 9 of the constitution had not changed.

Mr Abe announced in May he wanted to revise the US-drafted document to make clear the legitimacy of the armed forces by 2020, but said on Thursday that this should not be done on a fixed schedule.

Finance Minister Taro Aso and Chief Cabinet Secretary Yoshihide Suga kept their positions. Mr Itsunori Onodera returned to the role of defence minister after Mr Abe protege Tomomi Inada resigned from the post last week over a cover up involving military documents.

Two critics of Mr Abe got jobs: Ms Seiko Noda became Internal Affairs Minister while Mr Taro Kono, an advocate of immigration to ease Japan's demographic crisis, was appointed Foreign Minister.

Despite Mr Abe's policy of putting women in 30 per cent of management positions, the number of women in the Cabinet fell to two from three out of 19 positions.

"She tells me things even if they make my ears hurt," Mr Abe said of Ms Noda, who will also serve as minister in charge of the promotion of women. He added that he had tried to represent a range of views within the new Cabinet.

A general election does not need to be held until the end of 2018, but some analysts have speculated that Mr Abe will opt to call a poll this year to seek a fresh mandate. While his popularity has fallen, the opposition Democratic Party is also struggling, as it casts about for a new leader to boost its support beyond single figures.

With a party founded by Tokyo Governor Yuriko Koike yet to make significant inroads on the national stage, the LDP would face minimal opposition. Ms Koike ousted the LDP from power in the Tokyo assembly in an election last month.

Mr Abe's reshuffle may not help him win over voters, according to political science professor Koichi Nakano Sophia University in Tokyo."He'll be trying to regain his authority by turning a new page and getting rid of the problematic ministers. But he is also the source of the problem in many ways and he can't get rid of himself."