Liberal presidential candidate Moon Jae-in secured steady support as the front-runner, while centrist Ahn Cheol-soo saw his support drop sharply over the past week, surveys showed Monday.

The presidential race is set to enter its final stage. There are 10 days remaining before the two-day early voting, slated for May 4-5, and 15 days before the main May 9 election.

Since official presidential campaigning kicked off on April 17, Moon’s support rating has ranged between 37 percent and 43 percent, according to seven major opinion polls. The figure for Ahn stood at 26-32 percent.

Earlier this month, the gap between the two candidates narrowed to 1-4 percentage points, or within the margin of error.

A poll by Kantar Korea, which was released Monday, confirmed the widening disparity. Moon of the Democratic Party of Korea and Ahn of the People’s Party posted 37.5 percent and 26.4 percent in support ratings, respectively.

Six out of seven recent polls -- including by Kantar Korea -- recorded a gap of about 10 percentage points in their support. Only a poll by Embrain showed a 6.5 percentage point difference, with 40.7 percent of support for Moon and 34.3 percent for Ahn.

Political watchers share the view that Ahn fell short of the expectations of voters during TV debates after April 13. Some attribute Ahn’s waning popularity to his ambiguous stance over state issues, which could frustrate both liberal and conservative voters.

“Ahn’s supporter group is weak in terms of loyalty, as a large portion of them supports him based on anti-Moon sentiment,” said a spokesman of Research & Research.

He said that a proportion of supporters with weak loyalty to Ahn might have decided to support others after an alleged irregularity involving Ahn’s family came into the spotlight. He added that the weaker-than-expected performance of Ahn on televised debates could have disappointed supporters.

One upcoming issue for Moon is whether he will be able to garner support of 45 percent among the five major contenders, which also include conservative Hong Joon-pyo, conservative Yoo Seong-min and progressive Sim Sang-jeung.

Unless one candidate or more drops out of the race, it is hard to attain a majority in the election, political watchers agree.

Moon’s support is hovering at around 40 percent. His popularity is higher among those in their 20s, 30s and 40s.

However, according to Gallup Korea, his support among seniors still lags behind Ahn. Only 30 percent of respondents in their 50s and 17 percent in their 60s said they would vote for Moon.

There are three more debates scheduled for Tuesday, Friday and May 2.

The last advance polls must be released before May 3, the day before early voting begins. The Public Official Election Act bans poll results from being published from six days prior to the election, though surveys can still be conducted.

By Kim Yon-se (kys@heraldcorp.com)