Japan's incoming prime minister, Shigeru Ishiba, said he wanted to clean up his ruling party, revitalise the economy and see off security threats from powerful neighbours after triumphing in his fifth and what he called final leadership bid on Friday.

Japan’s governing party has picked former Defense Minister Shigeru Ishiba as its leader, setting him up to become prime minister next week.

Former Defense Minister Shigeru Ishiba, a plain-spoken populist, won leadership of Japan’s ruling Liberal Democratic Party in a runoff vote on Friday.