Japanese Prime Minister Fumio Kishida has said that he will remove his son from the position of his executive secretary amid mounting public outrage over a private party held at his official residence last year.

Kishida told reporters on Monday that his son, Shotaro, would step down as his executive secretary for political affairs due to “inappropriate behaviour”.

The move came after the weekly Shukan Bunshun magazine published photos showing Kishida’s son and his relatives at the prime minister’s official residence attending a year-end party on December 30.

The photos showed the guests posing on red-carpeted stairs in an imitation of the group photos taken of newly appointed Cabinets, with the younger Kishida at the centre – the position reserved for the prime minister.

Other photos showed guests standing at a podium as if holding a news conference.

“His behaviour at a public space was inappropriate as someone who is in an official position as a political aide. I’ve decided to replace him for accountability,” Kishida told reporters on Monday night.

He said his son will be replaced by another secretary, Takayoshi Yamamoto, on Thursday.

Kishida acknowledged that he had briefly greeted the guests, but said he did not stay at the dinner party.

He said he severely reprimanded his son for the event, but that failed to quell ongoing criticism from opposition legislators and public outrage, which have pushed down his support ratings.

Seiji Osaka, a senior legislator with Japan’s largest opposition party, the Constitutional Democratic Party of Japan, said the dismissal should have come earlier, Kyodo news agency reported.

“This is too late. I suspect [Kishida] appointed someone who is not capable [of being the] prime minister’s aide to the post,” Osaka was quoted as saying.

Chief Cabinet Secretary Hirokazu Matsuno earlier called the son’s party at the official residence “inappropriate” and promised to ensure proper management of the facility to prevent future misuse.

The nearly 100-year-old building was previously the prime minister’s office and became the living quarters in 2005 when a new office was built.

Kishida appointed his son as policy secretary, one of eight secretary posts for the prime minister, in October. The appointment, seen as a step in grooming him as his heir, was criticized as nepotism, which is common in Japanese politics, long dominated by hereditary lawmakers.

Shotaro Kishida was previously his father’s private secretary.

It was not the first time Kishida’s son has come under fire for making use of his official position for private activities. He was reprimanded for using embassy cars for private sightseeing in Britain and Paris and for buying souvenirs for cabinet members at a luxury department store in London when he accompanied his father on trips.

Kishida has also lost four ministers in three months over allegations of financial irregularities or links to the controversial Unification Church. (Al Jazeera)

•PHOTO: Japanese Prime Minister Fumio Kishida, right, appointed his son, Shotaro, left, as policy secretary in October [File: JIJI Press/AFP]

Update news