Members of the Democratic Party of Korea's Legal Committee hold a press conference in front of the Government Complex in Gwacheon, March 21. Yonhap

Five opposition parties submitted a motion to impeach acting President Choi Sang-mok on Friday over his non-appointment of a ninth justice at the Constitutional Court.

Lawmakers from the main opposition Democratic Party of Korea (DPK) and four minor parties submitted the impeachment motion at the National Assembly at 2 p.m.

"Despite a unanimous ruling by the Constitutional Court justices, (Choi) has not followed the ruling yet, though three weeks have already passed," Kim Yong-min, the DPK's deputy floor leader for policy, told reporters.

In late December, Choi appointed two justices to the court but held off on the appointment of opposition-recommended Justice candidate Ma Eun-hyuk, citing the need for a bipartisan consensus.

The DPK has strongly criticized Choi, noting the Constitutional Court's decision that Choi's non-appointment of the candidate is an "unconstitutional" act that infringes upon the right of the National Assembly.

The parties cited four other reasons for impeachment, including Choi's alleged involvement in President Yoon Suk Yeol's Dec. 3 martial law bid and the failure to appoint Supreme Court judge candidate Ma Yong-ju.

By law, an impeachment motion must be put to a vote between 24 and 72 hours after it is reported to a plenary session.

If National Assembly Speaker Woo Won-shik, who holds the authority to open plenary sessions, does not convene one before the deadline, the motion could be scrapped.

The opposition's move came as the Constitutional Court is set to deliver its ruling on Prime Minister Han Duck-soo's impeachment over martial law-related allegations next Monday. No date has been set for a ruling on the impeachment of Yoon.

Consent by at least six justices is necessary to uphold Yoon's impeachment, with the suspended president's fate in the hands of the nine-member court. Currently, the court has an eight-member bench. (Yonhap)