On 11 October 1985, while going to greet residents in Tuen Mun, he was savagely attacked with knives and metal pipes, hospitalising him for eight days.
Ng was elected as a member of the Legislative Council (LegCo) in 1991, and was noted for his hard work during his short term.
Ng was diagnosed with blood cancer in February 1992, but continued to work long hours, even making policy proposals from his hospital bed.
Despite his deteriorating health, on 4 June 1992 he attended a candlelight vigil in memory of the people who was killed during the Tiananmen massacre three years earlier.
He nevertheless took on the office and staff that Ng had run, and went to represent the area in Legco and on Tuen Mun District Council.