A new strain of flu from the northern hemisphere is likely to spread through Australia this winter, NSW health authorities say.
Centre for Health Protection director Dr Jeremy McAnulty says the new flu strain (H3N2) is likely to replace swine flu that emerged in 2009 as the dominant strain.
Pregnant women, the elderly and the chronically ill should be vaccinated.
"This may mean that people in older age groups may be at greater risk this winter," Dr McAnulty said in a statement on Monday.
"We are already seeing a rise in activity ... so now is the time to get vaccinated."
Free flu shots are available for people aged 65 and older, pregnant women, people with chronic illness as well as Aboriginal and Torres Strait Islander people.
Dr McAnulty said parents should arrange flu vaccinations for children older than six months, who were at relatively high risk of severe influenza.
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