A new survey released Friday indicated a growing popularity of liberal presidential hopefuls while support for conservatives eroded from the fallout of an accelerating corruption probe of President Park Geun-hye. 

Moon Jae-in, former head of main opposition Democratic Party, remained on top with 33 percent this week, up 4 percentage points from a week earlier, according to the poll conducted by Gallup Korea. 

He faces a growing challenge from South Chungcheong Gov. An Hee-jung of the same party, who surpassed the 20-percent mark for the first time.

The poll put An's rating at 22 percent, up 3 points from the previous week. It marks a 12-point increase in the span of two weeks.

In the third place, Acting President and Prime Minister Hwang Kyo-ahn and Rep. Ahn Cheol-soo of the People's Party tied at 9 percent. Hwang's approval rating fell 2 points while An's climbed as much.

Hwang has not yet expressed his presidential bid but is favored by the conservative bloc after former UN Secretary-General Ban Ki-moon dropped from the race.

They were followed by Seongnam Mayor Lee Jae-myung from the main opposition party with 5 percent and Rep. Yoo Seong-min of the Bareun Party with 2 percent.

By party, the Democratic Party posted an all-time high of 44 percent, followed by the People's Party with 12 percent, the ruling Liberty Korea Party with 11 percent, and the Bareun Party with 6 percent.

The survey was conducted on 1,003 voters from Monday to Wednesday. It has a margin of error of plus or minus 3.1 percentage points. (Yonhap)