The sudden closure came after 171 outbreaks of flu at kindergartens and childcare centres, and 177 in primary schools, from January 7 when flu season began.

Most schools were set to reopen on Monday, others resuming classes slightly earlier or later.

A father of a boy in third year of kindergarten, who gave his name only as Ng, said while he was still worried about infection, he could not have his son skip classes until flu season ends.

Hospital Authority chief executive Dr Leung Pak-yin earlier warned the winter surge was expected to last until the end of May.

“I will ensure my son wears a mask, remind him to wash his hands diligently, and pack antiseptic wipes in his bag,” Ng said.

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He noted that one child at his son’s school had been infected with the influenza B virus, adding that some parents had their children miss classes even before the government announced the early break.

But Ng said the kindergarten was being careful and he trusted it to step up precautions.

From January 21 to 31, there were eight such cases, and one of the children died.

But Ng expressed concerns that this number could go up when classes resume, with schoolchildren in close contact with each other again.

Nancy Lam Chui-ling, vice-chairwoman of the Federation of Education Workers and principal of Tsuen Wan Trade Association Chu Cheong Kindergarten, said even before the school closure it had reminded parents to have their children wear a mask. She said that in her school pupils have to wash their hands before entering classrooms.

Lam said parents also have to take pupils’ temperatures and record them for teachers to check daily – a practice adopted since the deadly outbreak of severe acute respiratory syndrome (Sars) in 2003.

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Henry Tong Sau-chai, chairman of the Committee on Home-School Co-operation, a government-backed committee to promote co-operation among schools and parents, said he had not heard of any schools planning to delay the resumption of classes or any parent wishing to keep their children home when schools open again.

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He said he heard of a school that planned to have children sit on the same side of the table during lunch, to reduce the risk of spreading flu.

Since the start of the current winter flu season on January 7 to last Wednesday, there have been 388 severe flu cases among all ages, including 230 deaths. Two of the deaths, and 15 of the severe cases, involved people under 18.