A respiratory health expert said on Sunday that the local influenza outbreak is easing from its peak, but warned that the winter peak is approaching.

David Hui, a respiratory medicine professor at the Chinese University of Hong Kong, told a Commercial Radio programme that the local influenza infection rate had dropped from 12 per cent last month to about six per cent last week.

"The summer outbreak of influenza started at the end of August. But then, by the middle of October and end of October, it has reached the peak with positive specimen around 12 percent and then starting to come down," Hui said.

"However, because of the cooler weather, one cannot be sure that this trend will be a bit more prolonged, requiring more than six to eight weeks from the peak to come down to the baseline."

He hopes that the summer outbreak will have returned to baseline levels by the end of November or early December.

Hui said that the winter flu season usually starts in January and ends in March. Even if the summer flu season subsides, a winter outbreak may follow shortly afterwards, he added.

"We should take advantage of the time to receive the influenza vaccination in preparation to the winter outbreak," Hui said.

Hui said that children are a high-risk group for catching influenza. During the summer flu season, there were at least 18 severe cases of flu in children, resulting in two deaths.

As only 14 per cent of children aged six months to two years have been vaccinated, he is calling on parents to ensure their children are vaccinated to reduce the risk of hospitalisation and severe illness.