Choo Kyung-ho, floor leader of the ruling People Power Party, speaks during a party meeting at the National Assembly on Tuesday. (Yonhap)

The ruling People Power Party threatened to launch a filibuster Tuesday if the opposition seeks to pass a contentious bill mandating a special counsel investigation into the military's response to a Marine's death last year.

The move comes as the main opposition Democratic Party is pushing to pass the bill and three broadcasting law revisions during this week's parliamentary plenary session despite objections from the PPP.

The special probe bill calls for a special counsel to look into allegations that the presidential office and the defense ministry inappropriately interfered in the Marines' investigation into the death of Cpl. Chae Su-geun, killed during a search mission for victims of heavy downpours in July 2023.

The DP-led bill had initially passed through the previous assembly but was voted down in a revote after President Yoon Suk Yeol vetoed it. The DP proposed it again after the new National Assembly came into office in late May.

Speaking to reporters at the National Assembly, PPP floor leader Choo Kyung-ho said his party will respond with a filibuster if the DP pushes ahead with the bills, which will effectively put Tuesday's regular session to a halt.

"If the introduction of the agenda items is pushed ahead, we will respond with indefinite debates," he said. "It is a long-kept principle and practice that no agenda items are introduced during parliamentary interpellation sessions."

An interpellation session was scheduled for later Tuesday, and the DP plans to deal with the contentious bills after the session.

A filibuster involves lawmakers holding the floor for extended periods as a way to prevent a parliamentary vote or delay the passage of a bill. (Yonhap)