To alleviate fears, it ordered schools to defer the summer break or other holidays. But many schools and parents say the policy is unnecessary, arguing that they have already made efforts to counter the loss of lesson time through Internet learning and other activities.

Dede Huang, director of development and external affairs at the Chinese International School, said: 'The Education and Manpower Bureau has said that the closure is to be treated as a school holiday, but schools are still required to provide work, exams are going ahead, and tuition is provided.'

She said that teachers were working on school premises, marking student assignments and answering queries about homework by e-mail and telephone.

Caroline Bickerton, a development officer at the Australian International School, said that the suspension period was not being treated as a holiday and that the school had no plans to interfere with its summer holiday schedule.

However, the EMB has said that even if schools are handing out extra work, they will still need to make up for days lost.

'We do not want the students' education to be affected,' said a spokeswoman. Schools would only be exempted from the policy in special circumstances and with backing of parents and school management bodies, she added.

Anissa Chan Wong Lai-kuen, who heads the Hong Kong Subsidised Secondary Schools Council, said the Internet learning activities some schools had designed for students should count towards class time. 'Schools should be allowed a degree of flexibility in making up for lost lesson time,'' said Dr Chan.

Kane Lee, an English teacher at a Kwun Tong secondary school, agreed. 'Delaying the summer holiday would be a waste of time. Students don't have the mood to study in July. It's too hot.'

Parent Christine Shirley, who has sent her daughter to stay with relatives in New Zealand during the Sars crisis, said making up for lost school time was not necessary. 'At the end of the day, after 13 years of education, missing two weeks is not going to make that much difference,' she said. She added that she thought schools were doing an effective job of dealing with the crisis.

The German Swiss International School said that it would not extend the school year. 'Lost time will be compensated by scheduling extra classes as necessary,' said spokeswoman Yasmin Farrell. Extra classes would take place in May and June.

The Yew Chung Education Foundation, which runs Yew Chung Hong Kong International School, said it would not consider the closure of the school as an extra holiday, since all its staff were on duty. 'We have sent homework materials online and by post every day,' a spokesman said.