Free flu shot programs have been extended in NSW, Queensland and Western Australia as hospitals continue to be inundated with people falling ill.
With more than 65,000 confirmed cases in May - more than double the month's previous record - Australia is in the grip of a heavy rebound influenza season following light caseloads during COVID-19 lockdowns.
NSW Health Minister Brad Hazzard wants more parents to take up the offer of free jabs, which will now run until July 17, for children during school holidays.
"It only takes a few minutes to get a flu jab, but that time could mean the difference between you or one of your loved ones ending up in ICU, so please, book in today," Mr Hazzard said on Thursday.
Almost 650,000 Queenslanders have so far taken advantage of free flu vaccines, but the state's rate of 35 per cent is still one of the lowest in the nation, says Queensland AMA president Maria Boulton.
"As of 19 June, we had already had 25,588 confirmed cases of flu in Queensland. During the entire flu season last year, we had fewer than 600 cases across Australia," Dr Boulton said.
"It is clear that we are in for a heavy and early flu season this year, with the double whammy of combined flu and COVID cases."
Queensland has also extended its program of free shots until July 17, while a similar offer in WA and SA will run throughout the month.
Health minister Amber-Jade Sanderson said all WA residents were eligible to walk in at state-run clinics or book vaccinations with participating pharmacies and GPs.
"More than 30 per cent of people have been vaccinated for influenza and we are hoping this trend can help us surpass 2020's record vaccination coverage of 37 per cent," she said on Thursday.
SA Premier Peter Malinauskas said the extension of free vaccines was a response to the unique challenge posed by COVID-19 and influenza cases at the same time, and the impact that was having on the state's under-pressure hospital system.
"This is the first year South Australia's health system has faced the challenge of a crossover of a COVID and flu season," he said.
"This extension will take us through school holidays and beyond, providing parents more time to get their kids protected."
About 798,000 flu vaccines have been administered in South Australia so far this year, compared with 701,000 at the same time last year.
Latest figures show there have been more than 6200 cases of influenza in South Australia in 2022, compared with less than 20 about this time last year.
SA Health said more than 100 people had also been infected with both influenza and COVID-19 within a seven-day period.
Australian Associated Press