Dr Ng holds a special interest in infertility (including male infertility), gynaecological laparoscopy and hormonal disturbances. He serves as an advisor to the Ministry of Health when there are issues related especially to infertility. He holds an adjunct professorship in the Dept of Obstetrics & Gynaecology, NUS, and in the School of Biological Science, Nanyang Technological University, where he lectures Development Biology.
Professor Ng is very active in research work. From 1997 to 2003, he was the Director of the World Health Organisation (WHO) Clinical Collaborating Center for Research in Human Reproduction and the WHO Clinical Collaborating Center for Maternal-Child Health / Family Planning Service Research and Training.