It's not too late to get the flu shot with "a lot" of influenza already circulating in Australia.
A mild-to-moderate flu season had been predicted but an infectious disease expert has warned against complacency.
Raina MacIntyre, Professor of Infectious Diseases Epidemiology at UNSW, says flu is always severe and people need to protect themselves by getting the flu vaccination as soon as possible.
"We always see people who die and get hospitalised because of flu, some years are worse than others," Professor MacIntyre said.
"You can get vaccinated all through the season, it's never too late," said Prof MacIntyre.
Flu activity traditionally peaks in July and August however the season is well and truly underway in Queensland.
Queensland Health's Influenza Surveillance Report shows there have been more than 4200 flu cases so far this year - 300 more than at the same point last year.
There has also been more than 500 hospitalised cases.
The start to the season has been a bit slower in NSW.
Data from NSW Health shows at the start of April there had been 658 influenza cases in NSW compared to 1126 during the same period last year.
"Influenza case numbers remain low in NSW and at this stage there is no indication of an early start to the flu season," said Dr Vicky Sheppeard, Director Communicable Diseases at NSW Health.
Nationally, there has so far been about 13,000 laboratory confirmed notifications of influenza, according to the Immunisation Coalition.
A similar number of influenza cases compared to this time last year have been recorded in South Australia, while the data shows activity is increasing in Victoria.
Influenza activity remains low in WA and in Tasmania.
The strains of flu people are falling ill with in Queensland have been a mixture of Influenza B and Influenza A (H1N1), there has also been some H3N2 - the strain responsible for the record number of influenza-related deaths recorded last year.
This could change and it's still too early to say how severe the nation's flu season will be, said Professor MacIntyre.
"Often what you see early in the season can change, for example during the 2009 pandemic early in the season we were seeing H3N2 and a bit of flu B and then the pandemic strain just overtook everything," Prof MacIntyre said.
