Doctors are urging people to get vaccinated against the flu before winter, with experts predicting a severe flu season is on the way.
Australian Medical Association (AMA) NSW President Brian Owler says the elderly and very young are particularly vulnerable.
But he's urging everyone - except those with a medical reason not to be vaccinated - to see their GP.
"When you get vaccinated, you're not just helping yourself and your family but everyone around you by stopping the spread of disease," Associate Professor Owler said in a statement on Monday.
He said the northern hemisphere winter brought with it a "very nasty form of the flu".
"The flu is more than a bad cold, it is an illness that can leave people very sick and even kill."
Prof Owler said people aged over 65, indigenous Australians 15 and over, pregnant women and people with specific chronic diseases could get the flu vaccine for free.
The NSW government on the weekend released a Get Ready For Winter plan for the flu season following record levels of infection in the northern hemisphere over the past winter.
One strain of influenza, H1N1, also known as swine flu, is expected to make a comeback after being responsible for several deaths in 2009.