A paediatrician on Saturday urged parents not to underestimate the threat of flu, saying both flu cases and child-hospitalisation have been on the rise.

Speaking on a radio programme, Dr Mike Kwan from the University of Hong Kong also warned of a so-called "tridemic situation" - a triple threat from the spread of flu, respiratory syncytial virus (RSV) and Covid.

"The precautionary measure of course is you need to receive the vaccine because vaccination is the ultimate protection for our children, and all the susceptible individuals like the elderly and the immunocompromised individuals," he told reporters.

"But apart from that, other measures like personal hygienic measures, wearing face masks in crowded places and poorly ventilated places, and also adequate hand washing... these are the most important."

Kwan also called on parents to arrange recommended jabs for their children, adding that those who are unvaccinated may become seriously ill after getting the flu.

The paediatrician added that respiratory viruses will continue to emerge with the lifting of Covid restrictions, adding that he expects the RSV infection to peak around March to April.