Japan's Regulatory Reform Minister Kono Taro plans to declare his candidacy in the Liberal Democratic Party's presidential race at a news conference on Friday.
The contest will decide a successor to the current LDP president, Prime Minister Suga Yoshihide. The post of main governing party president effectively carries with it that of prime minister.
Kono is also in charge of Japan's coronavirus vaccine rollout. He met Deputy Prime Minister and Finance Minister Aso Taro on Thursday to inform him of his plan to run. Aso heads an intraparty faction to which Kono belongs.
Kono has repeatedly met Aso to discuss his possible candidacy, and talked with former prime minister Abe Shinzo on Wednesday.
Kono decided to run as he apparently believes he has largely gained understanding within the Aso faction.
Official campaigning for the September 29 election is set to start on September 17.
Kono, aged 58, has been elected to the Lower House eight times from a constituency in Kanagawa Prefecture, neighboring Tokyo. He has also served as foreign minister and defense minister, among other posts.
The outspoken politician is the eldest son of former Lower House speaker Kono Yohei, who also served as LDP president when the party was out of power.
Former LDP policy chief Kishida Fumio and former internal affairs minister Takaichi Sanae have already declared their candidacies in the race.
The party's Executive Acting Secretary-General Noda Seiko has also indicated intent to join the race, while former LDP secretary-general Ishiba Shigeru continues to weigh whether to run.