According to the Realmeter survey, support for Moon edged down 1 percentage point from a week earlier to 58.9 percent this week.
The support score had hovered above 60 percent for five straight weeks, before falling to 59.9 percent last week.
The negative assessment on Moon’s conduct of state affairs inched up 0.2 percentage points over the week to 35.5 percent this week.
Support for Moon’s ruling Democratic Party rose 0.7 percentage points to 42.8 percent.
The main conservative opposition United Future Party gained 27.5 percent of support this week, up 1.2 percentage points from the previous week.
The results were based on a survey of 1,510 voters conducted from Monday to Wednesday. It had plus and minus 2.5 percentage points in margin of error with a 95 percent confidence level.