Influenza has killed 36 people in the last two weeks, more than the total number of deaths in last year's winter flu season, Centre for Health Protection figures show.
And deaths are expected to continue as a mutated form of the virus extends the flu season into next month. 'The virus has mutated and many people don't have the immunity,' Dr Lo Wing-lok, an infectious disease specialist, said. 'This year's winter peak has merged with the summer peak.'
The mutation is also rendering vaccination less effective, as most vaccines were based on a previous strain. Health specialists say the new strain has proved particularly dangerous for elderly people.
In the two weeks to Monday, 55 patients were admitted to intensive care wards with flu, while 36 people died. The number of flu cases recorded last week was the highest yet this year at 1,113.
Just 880 cases were recorded in the busiest week of last year and there were just 329 cases in the week from April 29 to May 3.
In the past four weeks, more than 95 per cent of influenza cases were of type A H3N2, replacing a milder strain recorded earlier in the year.
The centre said it would 'closely monitor' the local and international flu picture.
Severe influenza can lead to complications such as pneumonia in adults and encephalitis in children, the centre said. A growing proportion of people aged over 65 were among the seriously ill.
A spokesman for the centre said: 'Influenza activity is expected to stay high for some weeks to come, and we will continue to see some serious/fatal cases among all age groups, especially the elderly.'
The peak flu season usually ends in March. Between January 24 and March 31 last year, 34 people died of flu. Between January 24 this year and Monday, 128 people had died of flu.
The number of people given a flu shot via the government scheme since November is up this much from last year - with a total 233,000 vaccinated