Rep. Moon Jae-in, a lawyer-turned-politician, won his fifth straight victory in the ongoing regional primary contest of the Democratic United Party

(DUP) on Saturday, coming closer to securing the main opposition party's presidential candidacy ahead of the Dec. 19 polls.

Moon, formerly chief of staff to the late former President Roh Moo-hyun, garnered 16,350 votes, or 37.54 percent, of the 43,553 cast in Jeonju of North Jeolla Province, about 200 kilometers south of Seoul.

Compared with his overwhelming win in the previous four primaries in Jeju, Ulsan, Gangwon and North Chungcheong, however, Moon's overall polling share fell sharply.

Former Commerce Minister Chung Sye-kyun came second by winning

26.53 percent of the votes in the North Jeolla primary, followed by former DUP chairman Sohn Hak-kyu with 23.4 percent and former South Gyeongsang Province Governor Kim Doo-kwan with 12.52 percent.

The North Jeolla primary was seen as crucial, as the number of voters in the province was more than the combined total of the previous four regional primaries.

In all, Moon has secured 45.67 percent of all votes, followed by Sohn with 25.69 percent, Kim with 14.5 percent and Chung with 14.14 percent.

Moon's winning streak is not surprising as the 59-year-old candidate has led public opinion polls among the four hopefuls competing for the party's nomination. But the possibility of a run-off election has increased as Moon's rate fell below 50 percent.

The DUP is expected to announce the final winner of its regional primaries on Sept. 16 but if no candidate receives more than 50 percent of all votes cast, a run-off election will be held a week later. Political watchers say the Gwangju and South Jeolla Province primary slated for Sept. 6 will mark a watershed in the DUP race. (Yonhap News)