Pharmacies across Australia are reporting long waits for the flu shot as families rush to follow official advice to get vaccinated to avoid a dangerous "double-dose" infection during the COVID-19 pandemic.

While the flu vaccine offers no protection against COVID-19, doctors say it's one of the best things you can do to reduce pressure on the health system as it grapples with coronavirus crisis.

Experts have been urging everyone over the age of six months to get vaccinated for the flu in April to provide the best protection against the peak flu season, which starts in June.

But many pharmacists offering the jab with nurse practitioners to adults for around $30, including Chemist Warehouse and Priceline, are now booked out for the entire month of April, prompting concerns some will miss out or not be immunised in time for the flu season.

Despite the Morrison Government moving to secure the largest supply of seasonal influenza vaccines, the CSL group, which has been producing influenza vaccines in Melbourne, since the 1940s is now working to boost production.

Seqirus - owned by CSL - is the only local manufacturer of flu vaccines in the country.

"There's been extremely strong early demand for flu vaccines across all channels - GPs, pharmacies and other immunisation providers,'' Seqirus executive director Danielle Dowel told news.com.au.

"This is a good thing overall for important vaccine programs, especially this year as our health system deals with the concurrent COVID-19 outbreak.

"We've already distributed five million vaccines with more to come. There will be more flu vaccines being distributed across the country after Easter and into May, and we encourage people to phone their clinic or pharmacy ahead of time to ensure the vaccines have arrived and are available."

Hundreds of Australians die from the flu every year and it also results in thousands of hospitalisations and hundreds of thousands of GP consultations.

The symptoms of influenza and COVID-19 can also be similar and is likely to result in more tests for the coronavirus for people who simply have the flu.

Lockdown measures aimed at limiting the spread of COVID-19 and even simply washing your hands more often may actually reduce the number of flu cases this year, but experts are urging people to still get vaccinated.

Under new COVID-19 measures, all visitors to aged care facilities and childcare facilities need to have flu vaccinations from May 1 to enter the premises, increasing demand.

For the first time, a world-first 4-shot flu vaccine offering greater protection against more strains is also being offered this year in Australia and the publicity around the new vaccine has also increased bookings.

In a letter to doctors in March, the chief medical officer Professor Brendan Murphy stressed getting the flu jabs at the right time to ensure immunity was important.

"Vaccinating from mid-April provides protection before the peak season takes place,'' he said. "While protection is generally expected to last for the whole season, the best protection against influenza occurs within the first 3 to 4 months following vaccination."

Another reason why pharmacies are running low is that orders of flu season doses orders are finalised 6 months in advance of each flu season.

This allows manufacturers time to produce the vaccine. However, no one predicted the emergence of COVID-19 when this year's orders were placed.

Only adults can get vaccinated by private providers at pharmacies. The official advice is that everyone over the age of six months should get vaccinated.

But children still need to book in with a GP to get the flu shot.

There should be no shortage of jabs for over-65s which now receive the vaccine for free.

It's also offered for free to pregnant women and all children under the age of 5.

Families can access the flu vaccine through private providers including GPs and pharmacists and state and territory programs.

People who do not have COVID-19, or who are not a suspected case of COVID-19, are allowed to leave their home for a flu vaccination.

But Australian Medical Association President Dr Tony Bartone has urged people to phone ahead and make sure their health care professional has vaccine available and made an appointment.

"Influenza is a serious illness. It is preventable, and there is a very safe way to prevent that, and it's the influenza vaccine,'' he said.

To find a provider of the flu-shot you can call the National Immunisation Hotline on 1800 671 811.

Originally published as Rush to avoid 'double dose' of infection