Japan's major ruling party is making arrangements to summon former Prime Minister Shinzo Abe to parliament on Friday over allegations his office illegally covered part of the costs of dinner receptions for supporters, sources close to the matter said Wednesday.

The Liberal Democratic Party is considering having Abe appear at open sessions of the steering committees of both houses of the Diet or their board meetings, according to the sources.

File photo taken in April 2019 shows then Japanese Prime Minister Shinzo Abe addressing participants at a cherry blossom viewing party in Shinjuku Gyoen National Garden in Tokyo. (Kyodo)

The ruling party is set to enter detailed negotiations with opposition parties on Thursday, the sources said.

If summoned, Abe is expected to apologize for unintentionally making false remarks in parliament regarding the allegations based on his claim that he only recently learned of the scheme to cover part of the costs.

Opposition parties have been asking the LDP to allow Abe to be summoned to budget committees of both chambers of the Diet.

But the LDP wants to avoid having Abe take part in a budget committee session, where fierce questioning is common.

Tokyo prosecutors questioned Abe on a voluntary basis earlier in the week after a group managing his political funds was suspected of having spent more than 9 million yen ($87,000) to partially cover the costs of the receptions between 2015 and 2019 while failing to keep records of incomes and expenditures related to the events, as required by law.

The sources said the idea of Abe holding a press conference on Thursday prior to his appearance in parliament has also been floated.

Jun Azumi, the Diet affairs chief of the main opposition Constitutional Democratic Party of Japan, said that as long as Abe presents an explanation to parliament as soon as possible, he is flexible with the setting.

Assuming Abe's explanation is made public, "I don't care which committee session he appears at," Azumi told reporters.

The prosecutors are unlikely to indict the former prime minister based on claims that he was not aware his office covered a shortfall in costs for the events held at luxury Tokyo hotels, according to sources with knowledge of the situation.

Instead, they are planning to file a summary indictment against his state-paid secretary soon for allegedly not keeping the financial records.

A summary indictment is a simplified proceeding that skips court examination and applies to less serious offenses resulting in fines of 1 million yen or less.

Abe, who became the country's longest-serving prime minister before stepping down in September due to health reasons, has repeatedly denied any wrongdoing since the scandal came to light in November last year.