"I decided to take all the responsibility for offending many lawmakers in the process of pushing for the 'fast-tracking' (of the bills) and other difficulties faced by the party," he said after a meeting with party members.

Kim's term was originally slated to end in late June. His successor will be decided through another party meeting next Wednesday.

Last week, the ruling Democratic Party and three minor parties, including Bareunmirae, placed bills on election reform, on the establishment of a special unit to investigate corruption by high-ranking public and government officials and on the enhancement of the police's authority onto a "fast-track."

In a strong protest against the fast-track bid, the main opposition Liberty Korea Party has been staging rallies outside the National Assembly.

Last month, Kim replaced Bareunmirae's two lawmakers sitting on special panels handling the bills to ram through the fast-track bid, inviting strong condemnation from party members.

The Bareunmirae Party came into being in February 2018 through a merger of two minor parties with divergent support bases -- one center-right and the other left-leaning.

The merger of the two parties was viewed as a bold experiment in South Korean politics, in which regional loyalties remain strong. But party members have failed to integrate well due to the different personalities of their respective support bases. (Yonhap)