Former main opposition Democratic Party (DP) leader Lee Nak-yon and a group formed by lawmakers who defected from the DP in opposition to current leader Lee Jae-myung, jointly launched a new political party ahead of April's general elections.

DP-turned-independent Rep. Kim Jong-min, who had formed the "Grand Future Coalition" along with fellow defectors, Reps. Lee Won-wook and Cho Eung-cheon, jointly launched the "New Future" party with Lee Nak-yon on Sunday.

Reps. Lee and Cho, however, have decided against participation, posting on social media that they will not join the new party with hopes for a bigger unity based on the principle of horizontal integration.

The new party's name was decided as "New Future" after a contest participated by supporters, and it will be co-headed by Lee Nak-yon, who leads the party recruitment committee, and Kim. The election of other members of the party leadership has been delegated to the two-party chiefs.

While two sides had been at odds over creating a big tent party with the "New Reform Party," led by former ruling People Power Party (PPP) leader Lee Jun-seok and "New Choice," led by former DP Rep. Keum Tae-sup, both Lee and Keum were expected to attend Sunday's inauguration event.