Japanese vaccine minister Taro Kono will formally announce on Friday that he is joining the race to lead the ruling party, Kyodo news agency said.

That will make Kono the third candidate to replace Prime Minister Yoshihide Suga, who last week threw into disarray the contest for leadership of the Liberal Democratic Party (LDP) with a sudden statement that he would not run.

The party's majority in parliament virtually ensures that its leader will become prime minister. The leadership election is set for Sept 29.

(Reporting by Elaine Lies; Editing by Clarence Fernandez)