TOKYO (Kyodo) -- Prosecutors on Friday issued a summary indictment against a ruling party staff member in charge of accounting for the party in the Tokyo metropolitan assembly, alleging that he failed to properly report around 35 million yen ($224,000) in income, primarily from fundraising parties.

Hidekatsu Yajima, a 72-year-old accounting staff member, was charged with violating the political funds control law, the prosecutors said. The criminal case marks the spread of a slush funds scandal that has plagued Prime Minister Shigeru Ishiba's Liberal Democratic Party to the regional assembly level before key elections.

As a bookkeeper, Yajima has been responsible for preparing financial documents and other accounting duties for the LDP's assembly group. He has admitted to the charge, according to an investigative source.

The fundraising scandal, which surfaced in 2023 under Ishiba's predecessor, has eroded voter trust in politics. It has primarily involved LDP lawmakers and their intraparty factions, prompting opposition lawmakers to call on the LDP to thoroughly investigate the issue and enhance transparency.

In the latest revelation, the LDP's group in the Tokyo metropolitan assembly imposed a quota requiring its members to sell 50 tickets, worth 20,000 yen each, for fundraising parties held at a Tokyo hotel in December 2019 and May 2022.

They allegedly parked surplus funds at their disposal after meeting a quota of 1 million yen, according to a source familiar with the matter.

According to the indictment, Yajima failed to declare a total of around 35 million yen in income and around 28 million yen in expenses in the group's funding reports for fiscal 2019 and 2022.

Ishiba, who heads the LDP, apologized for the latest case and said the party headquarters will consult with the local chapter on "appropriate" measures to address the issue.

"By doing so, we will be able to regain trust in our party," he told reporters at his office.

More than 20 assembly members have been found to have failed to report income from the fundraising parties, including some who previously served as secretary general of the LDP's group in the metropolitan chamber, according to people with knowledge of the situation.

The LDP has 30 seats in the 127-member metropolitan assembly.

Yoshihiko Noda, who leads the main opposition Constitutional Democratic Party of Japan, stressed the need to check other local assemblies nationwide for any similar underreporting cases, noting that he had instructed a party executive to investigate.

The ruling coalition of the LDP and the Komeito party is keeping close tabs on the ramifications of the latest development for the assembly race in the summer, which precedes a nationwide election for the House of Councillors.

The assembly's election, though local, is seen as a barometer of what to expect in the upper house election, in which the ruling coalition aims to retain its majority. They lost control of the House of Representatives, the powerful lower house, last year.

"It's extremely regrettable. We already have supporters expressing their frustration," said Makoto Nishida, secretary general of Komeito.