NSW hospitals are continuing to feel the strain of an unusually long influenza season, with health authorities urging people to protect themselves as case numbers rise well into November and beyond.

More than 370 people presented to emergency departments across the state with an influenza-like illness in the week ending 16 November.

Health authorities warn that the true number of infections is far higher, with most people who contract flu never being tested.

“This time of year is usually when our hospitals and our staff get respite from the burden of respiratory illness, but this is not the case,” Mr Park said.

“Instead we are seeing sustained pressure on our EDs and on the staff who work there and across the wards.”

The latest NSW Health respiratory surveillance report shows influenza remains unusually prevalent in the community for late spring.

More than 3,100 influenza cases were notified in the week ending 15 November - the second consecutive weekly increase and similar to levels seen at the beginning of winter.

NSW Chief Health Officer Dr Kerry Chant said the state was experiencing “a longer tail” to the respiratory illness season than normal.

“Usually by September or early October influenza levels have tapered to quite low levels from the peak, which traditionally occurs during winter – but we are well into November and notifications are increasing,” she said at the time.

A person with the flu can be contagious for up to a week after symptoms start, and can also spread the virus for a day before they show any symptoms at all.

The extended season is expected to continue placing pressure on emergency departments into December, a time when Christmas and end-of-year gatherings typically increase the risk of spread.

“My worry, and the worry of our health experts, is that we’re seeing an increase at a time of year where people are rightfully getting together to celebrate – but the last gift we want to be giving each other is a dose of influenza,” Mr Park said.

People with mild illness, including influenza, are encouraged to use Healthdirect (1800 022 222) rather than attending an emergency department.

The 24-hour service connects callers with a nurse, who can organise a video consult with a doctor, nurse or allied health professional if needed.

Healthdirect has logged more than 50,000 calls from people reporting respiratory symptoms during the extended flu period, with over 65 per cent of those callers safely managed through alternative care pathways.

Dr Chant urged people to take preventive steps as the season drags on.

“No one wants influenza, or any respiratory illness for that matter, to ruin the end of their year,” she said.

“It’s not too late to get vaccinated.

"If you are sick, please stay home, and wear a mask if you need to go out, to help stop the spread.”

She also encouraged people at higher risk of complications to have a plan in place with their GP, including access to antiviral medication if needed.

For more information on respiratory illness or to book a flu vaccination, visit the NSW Health respiratory information page.