More than 7,900 students had signed the petition by last night.

In the petition letter, Wynne expressed students' fears that the reopening of schools could result in a sharp rise in infections.

'Diseases are impartial. They attack everyone, including secondary and primary school students. Why should the older students be used as guinea pigs?'' she wrote.

Form Four student Mana Tang, from Sha Tin, who forwarded the petition to the South China Morning Post, said: 'Many of my friends are very worried. We will remain at home for another week if our parents allow us to.'

A 14-year-old supporter of the petition wrote: 'Which is more important, our lives or education? Without health there is no education to speak of.'

Even a nine-year-old wrote of her concerns. 'My elder sister has to return to school. I don't want her to fall ill,' she said.

Mana believed schools should remain closed until the outbreak was fully under control. She would not mind studying throughout the summer break if necessary.

'The government says it is safe to go back to school. But when we watch the television every day we see people are dying and the number of cases are increasing,' she said. 'We can't understand why the government wants us to return.'

The bureau, however, expects most students to return to school. 'We do not encourage students to remain at home, unless they are feeling unwell or have other special concerns,' said a bureau spokeswoman.

She said the accompanying precautions - which include having students' temperatures taken at home and asking them to wear masks, as well as quarantine measures for those who have had contact with Sars patients - were adequate. Adding the decision was made after much consultation, the the spokeswoman said: 'This is not an easy decision. We have to balance the need of all parties.'