The National Assembly is set to begin an extraordinary session on Monday as rival parties remain at odds over a range of issues. 

Floor Leader Joo Ho-young of the main opposition United Future Party(UFP) told reporters on Sunday that his party will return to parliament and participate in assembly and standing committee sessions.

Vowing they would fight against the ruling Democratic Party(DP), Joo called for parliamentary inspection into the government's North Korea policy and controversy surrounding DP lawmaker Youn Mee-hyang. He also called for an independent probe into a scandal involving a senior prosecutor close to Prosecutor General Yoon Seok-youl.

However, the ruling party rejected the call for parliamentary inspection immediately, calling it "unacceptable." The party also plans to respond to the call for an independent probe after looking into details of the case. 

First vice floor leaders of the two parties held a meeting on Sunday afternoon to discuss the schedule for the extra assembly session, but ended the meeting without agreement.