The justice minister's nephew is also facing a prosecutor's probe into his role related to a private equity fund in which Cho and his wife invested.

The LKP staged back-to-back protest rallies at the National Assembly compound and Gwanghwamun in Seoul on Sunday, demanding the dismissal of the minister.

"This fight is not against Cho Kuk. It's against the socialist Moon Jae-in administration," the party's chief, Hwang Kyo-ahn, said.

Where Cho should go is not the Ministry of Justice but an interrogation room, he added.

Hwang claimed that a growing number of people are talking about ousting the Moon government.

Rep. Na Kyung-won, the LKP's floor leader, said many people have withdrawn support for Moon and become swing voters. She vowed every possible effort to lure them to support her conservative party.

She said the LKP will push for a no-confidence vote against Cho, a special parliamentary probe into the scandal involving his family and even the appointment of an independent counsel.

The LKP is moving to form an "anti-Cho Kuk coalition" with the center-right opposition Bareunmirae Party.

It plans to hold a meeting of all of its lawmakers on Monday to discuss detailed strategy.

Starting from Tuesday, the floor leaders of political parties will deliver National Assembly speeches as part of its regular session.

Next week, an interpellation session will take place before the parliamentary audit season from Sept. 30-Nov. 19.    

The LKP plans to focus its fire on attacking Cho as well as Moon for his justice minister pick.

On the other hand, the ruling bloc plans to accelerate its reform drive.

Rep. Cho Jeong-sik, the policy chief of the Democratic Party (DP), said the appointment of the new justice minister reflects the Moon administration's determination to push incessantly for the reform of the prosecution and other influential institutions.

"The government and the (ruling) party will mobilize all capabilities for the systemic completion of reform," he said.

The party plans to hold consultations with the justice minister around Wednesday on ways to reform the prosecution.

The DP will also concentrate efforts on modifying the college entrance exam system and revitalizing the economy.

The people want the National Assembly to get out of the "Cho Kuk black hole" as early as possible and handle issues associated with their lives, Rep. Park Chan-dae, the DP's floor spokesman, said. (Yonhap)