"There are probably many more who are keeping quiet because they are too embarrassed to come forward," V. Atputharajah, the doctor who runs the centre, told the Straits Times.

The number of people going to the clinic at the K K Women's and Children's Hospital had not dropped, despite better access to information on sex and reproduction on the Internet and in books and through sex education at schools, Dr Atputharajah said.

While there are no official figures on unconsummated marriages in the city-state, Dr Atputharajah estimated that one couple in 200 had the problem. Chong Yap Sent, an associate consultant at the National University Hospital, said the figure was probably twice to four times as high as that.

Many couples seek help to find out why they are not conceiving, the report said. Some couples claimed to have sex regularly, but examinations found that the women's hymens were intact. A higher proportion of Indian couples turn out to have the problem compared to other races, the hospital found.

Dr Atputharajah enrols patients on a course to help them understand their bodies and sexual intercourse. The hospital offers special therapy sessions. "Some have gone on to have children while others simply learn to enjoy sex," the report said.