A survey indicated Friday that South Korea's leading presidential contender probably won more than half the votes in his party's first in-house election earlier this week.

Moon Jae-in, former chief of the liberal Democratic Party, was supported by 51.1 percent of those who were asked to choose their favored contender in the first round of the primary held Wednesday, according to Realmeter. The vote was conducted over two days starting on Tuesday.

The outcome of Wednesday's vote will be revealed later after being combined with the results of telephone surveys and additional votes by party members.

If Moon wins a majority after the final primary on April 3, he will be named the standard-bearer for the May 9 presidential election. If not, the party will hold a run-off, in which his rivals may join forces to challenge the frontrunner.

The other candidates are South Chungcheong Gov. An Hee-jung, Seongnam Mayor Lee Jae-myung and Goyang Mayor Choi Sung.

But even in a hypothetical run-off, Moon beat An with 60.2 percent against 33.8 percent, and Lee with 58 percent against 29.7 percent, the survey showed.

Moon, who served as chief of staff to late former President Roh Moo-hyun, took first place among all presidential candidates with 36.2 percent. He led among all regions and generations, with the exception of the northeastern Gangwon Province and those aged 60 or older.

An came second with 18.4 percent, followed by Ahn Cheol-soo of the centrist People's Party at 12.1 percent and Lee with 11 percent.

South Gyeongsang Gov. Hong Joon-pyo of the Liberty Korea Party came fifth with 8.6 percent, posting the highest rating among conservative candidates. Rep. Kim Jin-tae, an outspoken loyalist to former President Park Geun-hye from the same party, ranked sixth at 3.8 percent.

The survey was conducted on 2,250 adults nationwide and had a margin of error of 2.1 percentage points at the 95 percent confidence level. (Yonhap)