She was responding to the release of a study by University of Worcester in the UK which showed that worldwide primary school pupils spent an average of 105 minutes per week on PE while at secondary the average was 103 minutes, a decline from 2000.

Professor Ha said Hong Kong's primary and secondary students spent between 40 and 70 minutes on physical education each week, based on data given to the Education and Manpower Bureau by schools and teachers' feedback.

'Hong Kong is in fact leading this trend,' Professor Ha said. 'We have much less PE time than many other countries, not just in Europe but also in Asia. One of the underlying reasons is that schools and parents put academic [success] before the health of their children.' Professor Ha surveyed 2,400 Hong Kong students aged 10 to 16 on their exercise patterns and attitudes towards physical education, as part of a study conducted with an Australian university due to be released next month.

While about 70 per cent of boys in both countries said they liked PE, Hong Kong girls were less likely to say they enjoyed PE than Australian girls. In Hong Kong, 18 per cent of 16-year-old girls said they enjoyed PE compared with 55 per cent in Australia.

'When they get older, it seems that [Hong Kong girls] are not spending time on physical activity. The attitude becomes more negative. Girls seem to enjoy more sedentary activity,' Professor Ha said.

The survey also asked students why they did not take part in more physical activities. While boys' reasons included not having enough time or energy, one of the most common reasons given by girls was that exercise was not regarded as important by their families.

Professor Ha, who also interviewed parents, found that some sent their daughters a message that it was not good to be too active and that exercise was not important.

'They think health is important but when the child is getting older and enters secondary school, the academic part becomes more important than anything else.'

The Curriculum Development Council recommends that 5 per cent to 8 per cent of curriculum time should be allocated to PE at primary and junior secondary school. In senior secondary, at least 5 per cent of the curriculum time should be devoted to PE.

Professor Ha said based on these recommendations, students should spend between 90 minutes and 144 minutes on physical education each week. However, this was not happening in most schools.

'Some schools even use PE time as a make-up time for other academic subjects,' she said.

Duncan Macfarlane, associate professor at the University of Hong Kong's Institute of Human Performance, said: 'When you look at the data it clearly suggests ... that Hong Kong's children are probably the most inactive in the world.'

Dr Macfarlane blamed a number of factors, including the city's lack of space and parents and schools not allowing children to go outside to play.

An EMB spokeswoman said most schools allocated adequate curriculum time to PE. 'Schools also organise adequate PE-related ... activities including interest groups and different kinds of recreational or competitive sport events,' she said.