Those who disapproved of his performance made up 24.6 percent, up 1.2 percentage points from the previous week, while 5.9 percent said they were unsure or refused to answer.

The pollster attributed the drop in Moon's public support partially to his political adversaries' criticism of what they call "humiliating" diplomacy with Beijing.

Moon is set to hold a summit with his Chinese counterpart Xi Jinping on Thursday, but the two sides agreed not to issue a joint statement due to their differences over the deployment of a US missile defense system.

In response to China's security concerns about the Terminal High Altitude Area Defense system, the Moon administration has stated its stance against additional THAAD deployment, its participation in the US-led missile defense network and the creation of an alliance among South Korea, the United States and Japan. But opposition parties call this stance humiliating diplomacy.

The survey put the approval rating for the ruling Democratic Party at 53.3 percent, up 4.2 percentage points, while that of the main opposition Liberty Korea Party was tallied at 19 percent, up 1.2 percentage points.

The People's Party garnered 6.1 percent, while the Bareun Party and Justice Party received 4.7 percent and 3.5 percent, respectively.

The survey, commissioned by local broadcaster CBS, was conducted on 1,507 eligible voters. It had a margin of error of 2.5 percentage points with a 95 percent confidence level. (Yonhap)