The National Assembly was set to vote Thursday on two separate motions seeking the arrest of opposition leader Lee Jae-myung and the dismissal of Prime Minister Han Duck-soo.
The motions will be put to an anonymous vote during a plenary session in the afternoon.
The motion requesting parliamentary consent to lift the arrest immunity of Lee of the main opposition Democratic Party came after the prosecution sought an arrest warrant for him over breach of trust and other charges.
By law, sitting lawmakers are immune from arrest while parliament is in session and can be arrested only when the National Assembly consents to it. But the privilege came under criticism that it is abused to protect corrupt politicians.
Lee has been accused of breach of trust, bribery and other charges in connection with a scandal-ridden land development project and involvement in a company's illegal cash remittance to North Korea.
In order for the motion to pass, it requires a majority of the assembly members to vote and a majority of those voting to cast their ballots in favor.
The motion, however, can be rejected if Democratic Party lawmakers vote against it, as the party holds a majority with 167 seats in the 297-member parliament. The vote is expected to be cast by 295 lawmakers, excluding Lee, who has been hospitalized, and an independent lawmaker under detention.
Lee, who has been on hunger strike for nearly three weeks in protest against government policies, called for the motion's rejection, even though he had earlier promised to give up the privilege of arrest immunity.
In February, the prosecution's attempt to detain Lee on allegations of corruption in two separate corruption cases fell through after parliamentary disapproval.
Separately, the Democratic Party submitted the motion seeking Han's dismissal to the parliament Monday, accusing him of serious incompetence as chief of the Cabinet and holding him responsible for President Yoon Suk Yeol's policies.
However, Yoon is expected to reject the motion, despite it being highly likely to pass.
The Democratic Party has passed two dismissal motions since the launch of the Yoon administration -- one against Foreign Minister Park Jin and another against Interior Minister Lee Sang-min. Both were rejected by the president. (Yonhap)