In the same survey, 14.2 percent disapproved of Moon's performance, up 4.2 points from the previous week, while 7.7 percent said they were unsure.

"It appears that some of his supporters withdrew their support amid the attacks on his Cabinet nominees during the parliamentary confirmation process and the opposition's offensives over the THAAD report omission," the pollster said.

Last week Moon ordered an investigation into what he claimed was the defense ministry's failure to report the deployment of four additional launchers of the US THAAD missile defense system in South Korea. The move sparked backlash from opposition parties, which accused the administration of incompetence.

Moon's approval rating fell the most in the capital area of Gyeonggi Province and Incheon (8.3 points), followed by the conservative stronghold of Daegu and North Gyeongsang Province (6.9 points) and the central region of Daejeon, Chungcheong and Sejong (6.5 points).

By age group, the president lost the most points among those aged 60 or older (11 points), followed by those in their 40s (5.8 points) and 50s (5.5 points).

On Moon's expected performance in the future, 77.7 percent said they expect him to do well, 5.2 points down from a week earlier, while 14.6 percent said they don't expect him to do well, up 4.2 points in the same period.

The survey was conducted on 2,527 adults and had a margin of error of 1.9 points at the 95 percent confidence level. (Yonhap)