Democratic Party of Japan lawmaker Junichiro Koga told party executives Tuesday he will leave the party but vowed not to resign his Diet seat for making false claims about his academic background.

The scandal is widely seen as a slap in the face to the opposition DPJ, which boosted its presence substantially in the House of Representatives in the November general election.

Koga told DPJ leader Naoto Kan and Secretary General Katsuya Okada he will leave for causing an uproar over his academic career, in which he falsely claimed while campaigning in his Fukuoka district for his first Lower House seat that he had received a bachelor's degree from one California university and attended two others.