The negative assessment on Moon's conduct of state affairs slipped 1.5 percentage points to 55.3 percent, according to the Realmeter survey.
Support for Moon's ruling Democratic Party fell 0.4 percentage points to 32.7 percent last week.
The main conservative opposition People Power Party won 37.2 percent of support last week, down 2.0 percentage points from the previous week.
The minor center-right People's Party gained a 7.9 percent of approval score, followed by the minor center-left Open Democratic Party with 6.4 percent and the minor progressive Justice Party with 3.5 percent.
As for the approval rating of presidential candidates, support for the Democratic Party's Lee Jae-myung advanced 1.7 percentage points over the week to 39.7 percent last week.