A vote is mandatory following a general election, and Ishiba is expected to be re-elected in a runoff against the top opposition leader Yoshihiko Noda.

The Japanese parliament on Monday re-elected Liberal Democratic Party chief Shigeru Ishiba as prime minister in a rare runoff vote after the ruling LDP lost its majority in the lower legislative chamber.

Parliament voted Monday to stick with Mr. Ishiba, who will lead a minority government after his party suffered heavy losses in an election last month.