South Korean President Moon Jae-in's approval rating has fallen to 47 percent, as he marked his second anniversary of his inauguration on Friday.
The figure released by Gallup Korea is almost half the rating of 84 percent achieved by Moon shortly after he took office.
Supporters of the president cite his efforts to improve ties with North Korea. Moon held three summits last year with the North's leader, Kim Jong Un.
But inter-Korean relations have been at a standstill since the second US-North Korea summit collapsed in February over the issue of denuclearization.
North Korea's firing of two projectiles on Thursday, the second such incident in less than a week, has further reduced the prospects for a resumption of dialogue between the two Koreas anytime soon.
The top reason for the respondents' disapproval of Moon is dissatisfaction with his economic policies. Raising the minimum wage has adversely affected the job market.
South Korea will hold general elections in April next year. NHK's correspondent says Moon will have to deal with the country's soured relations with Japan and other difficulties in the remaining three years of his term.