Gyeonggi Province Gov. Lee Jae-myung has surpassed Democratic Party Rep. Lee Nak-yon for the first time in a popularity poll of South Korea's prospective presidential candidates, pollster Gallup Korea said Friday.

In a Gallup survey of 1,001 adults nationwide conducted from Tuesday to Thursday, Gov. Lee was favored by 19 percent of respondents, beating out his political rival Rep. Lee, who obtained support from 17 percent.

The governor's endorsement rate rose by 6 percentage points from the previous month, whereas the lawmaker's rate dived by 7 percentage points, Gallup said.

Gallup said it asked the pollees to pick their favorite presidential hopeful without presenting candidate names.

Rep. Lee, who formerly served as prime minister, had held onto the top post in surveys of presidential hopefuls for seven months but was overtaken by Gov. Lee for the first time, Gallup said.

Prosecutor General Yoon Seok-youl remained in third place with a popularity rate of 9 percent, while former presidential candidate Ahn Cheol-soo, who heads the minor People's Party, and independent lawmaker Hong Joon-pyo garnered support from 3 percent and 2 percent, respectively, the pollster noted.

By region, Gov. Lee is the most popular prospective presidential candidate in the Seoul metropolitan area, the central regions of Daejeon and Chungcheong provinces, and the southeastern regions of Daegu and North Gyeongsang Province. Rep. Lee is overwhelmingly popular in the southwestern regions of Gwangju and South Jeolla Province and maintains a lead in Busan and the surrounding South Gyeongsang Province.

By sex, male respondents (25 percent) favored Gov. Lee, and female respondents (18 percent) preferred Rep. Lee. The poll has a margin of error of plus or minus 3.1 percentage points, with a confidence level of 95 percent.

"Despite the reversed endorsement rates of the two Lees, it's still difficult to determine who is dominant, as presidential candidates are usually elected through intra-party competition. Rep. Lee is ahead of his rivals among Democratic Party supporters, while the two show similar popularity rates of around 30 percent among liberals," said a Gallup Korea official. (Yonhap)