Infectious diseases expert Ivan Hung said on Saturday that children should get their influenza vaccinations ahead of the Lunar New Year to anticipate an expected flu spike in kindergartens and primary schools.

Speaking on a radio programme, the University of Hong Kong professor said children as young as six months old can get the flu jab.

While getting vaccinated is highly recommended, he also reminded the public of the need for personal hygiene.

"Children at school should wash their hands frequently and, of course, if they have symptoms of influenza or flu, then they should not be going to school, they should be staying at home. Of course, if they have minor symptoms, then they could wear a mask and still go to school," he said.

"I think these are the important measures, but most important of all is still getting the influenza vaccine for children. There's still enough time to get the vaccine before the Chinese New Year."

Hung also said a significant number of people returning to Hong Kong from Japan have exhibited flu symptoms, possibly due to the colder winter temperatures in Japan.

"For those who are just coming back from overseas, then of course, if they have symptoms of influenza or flu, then they should be seeing doctors. They should do a rapid test and they could see a doctor and get treatment," he said.

"It's usually quite minor for children, so they could get a Panadol, paracetamol, some nasal decongestants, some medication for that. I would recommend staying at home until they fully recover before going to school."