The main opposition Democratic United Party (DUP) and the leftist minor Unified Progressive Party (UPP) will select 16 UPP candidates and hold primaries in 76 districts to field the most competitive contender, according to a joint statement signed by the parties' leaders.
Chairwoman Lee Jeong-hee of the United Progressive Party (L), Chairwoman Han Myeong-sook of the Democratic United Party (R) (Yonhap file photo)
DUP Chairwoman Han Myeong-sook and UPP Chairwoman Lee Jeong-hee had earlier agreed to field unified candidates in some key districts and conduct a joint campaign on main election pledges. The most contentious issues ahead of the vote are the free trade agreement with the United States and a controversial naval base project on the southern resort island of Jeju.
Through rounds of negotiations, the two leaders said they will oppose the trade pact due to go into effect on Thursday and push to stop the ongoing construction of the naval base.
The alliance move for the April vote has been closely watched as the election results could further affect liberals' bid to win the presidential race in December.
It is the first time in two decades South Korea will elect a new parliament and a new president in the same year.
The DUP was born out of a merger between the main opposition party and a novice party in December, while the UPP was established through a merger of three minor progressive parties during the same month.