Four Japanese opposition parties and a group jointly submitted a no-confidence motion against the Cabinet of Prime Minister Shinzo Abe in the Lower House on Tuesday.
The ruling camp is expected to vote down the motion in the chamber's plenary session in the afternoon.
The leaders of the Constitutional Democratic Party of Japan, the Democratic Party for the People, the Japanese Communist Party, the Social Democratic Party and the Reviewing Group on Social Security Policy met on Tuesday morning.
They agreed to introduce the motion to clarify their aim to remove Abe's Cabinet from power.
They said the Cabinet continues to deceive the public on domestic and foreign affairs, and is jeopardizing the people's lives and security.
CDP leader Yukio Edano said they all agreed on the move to demonstrate their opposition to the failing Abe administration.
The acting secretary-general of the main governing Liberal Democratic Party, Koichi Hagiuda, said the ruling camp deeply appreciates the Cabinet's efforts. He said the Cabinet does not deserve to be censured and ousted, and that the ruling coalition will reject the motion.
The political battle is heating up one day before the ordinary session is set to end on Wednesday.