Former Japanese senior vice justice minister Mito Kakizawa resigned as a lawmaker on Thursday after being indicted for violating the election law by allegedly engaging in illegal campaign financing related to a Tokyo ward mayor election.

Mito Kakizawa. (Kyodo)

Kakizawa, who left the ruling Liberal Democratic Party headed by Prime Minister Fumio Kishida before he was arrested in late December, has admitted to the infraction of the law and expressed his intention to step down as a lawmaker, sources close to him said.

A House of Representatives by-election to fill Kakizawa's seat in Tokyo is scheduled to be held on April 28, along with two others, posing a test for Kishida as approval ratings for his Cabinet have been sluggish amid a slush funds scandal involving the LDP.

Kakizawa, the son of a former foreign minister, is suspected of making payments, or having offered to do so, totaling 2.8 million yen ($19,000) as bribes in connection with the Koto Ward mayoral election in April last year, the sources said.

The election law violation allegations emerged following revelations that Kakizawa had proposed using an online advertisement, prohibited by law, for the campaign of Yayoi Kimura, the candidate he backed in the mayoral race.

Kakizawa resigned as senior vice justice minister in October, while Kimura, who was indicted without arrest, stepped down as mayor in November.

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