Chief Executive Donald Tsang Yam-kuen's popularity has fallen further after the government's delayed decision to send chartered flights to bring home Hongkongers stranded in Thailand early this month.
The incident also led to a drop in the public's ratings for the government's ministerial, or accountability, system, a study by Chinese University found.
The administration initially refused to send chartered flights to pick up residents stranded in Bangkok, but later made a U-turn after a couple from Hong Kong were involved in a traffic accident, in which the husband was killed.
In the survey, conducted in mid-December, the chief executive was given 50.7 marks out of 100, down from 51.5 in November. The pass mark is 50.
Mr Tsang's popularity began to fall in June, when he scored 59.2 marks, 6.4 down on the May figure. His rating has not risen since.
Respondents gave the 'accountability system' 42.5 marks, down from 45.1 last month. This rating has been below the pass mark since July.