The ruling Democratic Party (DP) and the splinter minor Open Democratic Party announced their merger agreement Sunday, in a move meant to strengthen unity in the liberal political bloc ahead of the March 9 presidential election.

DP leader Song Young-gil and Choe Kang-wook, the head of the satellite party, signed the agreement, including a decision to use the ruling party's name as that of the merged party, along with a set of political and social reform goals.

The agreement came as Lee Jae-myung, the ruling party's standard-bearer, has been stepping up his presidential campaign against Yoon Suk-yeol, the nominee for the main opposition People Power Party. Polls have shown them in a neck-and-neck race in recent weeks.

The two parties' merger agreement entailed their political reform agenda, including adopting an open nomination system for proportional representation parliamentary seats and seeking a system to allow citizens to recall lawmakers. Their social reform agenda included installing a real estate market oversight institution.

The minor party is considered a "satellite party" of the DP, as it was launched by former DP lawmakers ahead of last year's parliamentary elections. The party went on to win three proportional representation seats in the National Assembly. (Yonhap)