The Bareun Party, which spun off from the ruling Saenuri Party as a parliamentary negotiation body in December, will officially become an independent party on Tuesday.
After about a month of preparation, it will become the No. 4 party in the 300-seat National Assembly with more than 30 lawmakers.
Earlier this week, the Bareun Party designated Rep. Choung Byoung-gug as its chief while naming members of its decision-making Supreme Council.
The splinter party came as a result of a factional feud in Saenuri involving loyalists to President Park Geun-hye and her dissenters. Park, also a Saenuri member, was impeached by parliament in December on allegations of corruption.
Amid the possibility that South Korea could hold its next presidential election earlier than expected due to the impeachment, the Bareun Party is expected to speed up its efforts to find potential candidates.
Later this week, Gyeonggi Gov. Nam Kyung-pil and Rep. Yoo Seong-min, potential contenders from the party, are expected to announce their presidential bids.