HONG KONG More than half of Hong Kong's schoolchildren do not get enough sleep because of exam and homework pressure, a survey published Friday found.

Eight out of 10 students in some age ranges told researchers they slept for an average of 6.8 hours per night. Doctors recommend children have eight hours sleep.

Fifty-four percent of the 600 schoolchildren questioned by the Hong Kong Federation of Youth Groups said they had not had enough sleep in the past three months, DPA reported.

Students said the main reasons for lack of sleep were too much homework and exam preparation. Other reasons were watching TV and using the Internet.

A government review of Hong Kong's schooling system is underway amid criticism that it is too exam-oriented and puts its pupils under too much pressure with excessive homework loads.