Chief Cabinet Secretary Yoshimasa Hayashi announced the four-day special Diet session on Tuesday, where Ishiba is likely to garner more parliamentary support than opposition challenger Yoshihiko Noda of the Constitutional Democratic Party of Japan (CDPJ).
The Democratic Party for the People (DPP), a smaller opposition group, has indicated it will back its own leader Yuichiro Tamaki in the prime ministerial vote, a move that could inadvertently benefit Ishiba by splitting the opposition vote, political analysts said.
The leadership contest comes as Japan grapples with mounting inflation concerns, with the Liberal Democratic Party (LDP) and opposition groups seeking common ground on economic relief measures.
