The swine flu, or H1N1 virus, is sweeping through Australia with the virus accounting for the majority of the rising number of influenza cases this year, experts said Tuesday.

The Influenza Specialist Group (ISG) said Australia is experiencing double number of cases than at the same time last year with more than 21,000 reported cases of influenza so far.

Almost three quarters of the reported influenza cases for 2014 were the H1N1 strain.

ISG chairman Dr Alan Hampson said the latest outbreak of swine flu was the main reason for the severe flu this year.

Hampson said regular people, and not just the elderly, were suffering from the virus.

"People tend to think of the flu as an illness that has its worst impact on the elderly," he said in a statement. "The reality is that influenza results in 18,000 hospitalizations every year. Many of those seriously affected are not elderly people. They are regular working people."