There are more Australians suffering from flu this year than last year and experts are baffled by the rise of cases before the August and September peak seasons.

There have been 8000 reported influenza cases this year in Australia compared with only 2000 at the same time last year. In January and February alone there were more than 1700 people already suffering from influenza, compared with just 300 cases last year in the same time.

Influenza rates in the summer and autumn were higher than any in the past decade according to Alan Hampson, an adviser to the World Health Organization and the federal government.

''It has been a very unusual year,'' he said. ''Based on what we have seen this year we might expect a severe flu season.''

Bad weather and flooding in certain parts of the country could be the reasons for the unnaturally high flu cases. Researchers are still uncertain why high rainfall and cold weather made flu cases rise said Dr. Hampson, chairman of the Influenza Specialist Group. The group, who is looking to reduce the impact of flu and search for a flu vaccine, theorizes that the weather itself could be a factor as it drove people to spend more time indoors and group together in enclosed spaces like malls or theater leading to the virus being passed on.

Dr. Hampson also warned people at high risk from flu such as the elderly or those with chronic health conditions to get to their local GPs and get vaccinated.

''But it is coming down to the line in terms of getting a shot that will protect you,'' he said.

Flu vaccines start working about one week after they are given. Those who are already infected with the flu should take prescribed antivirals to reduce the length and severity of the illness.

Pregnant women and the overweight should also be on the alert as they will be more susceptible to the dominant form of the virus, the swine flu.

Despite the high number of flu cases, patients don't need intensive care like the swine flu pandemic of 2009.