Australians under 40 will not be eligible for Pfizer coronavirus jabs ahead of schedule despite increasing hospitalisations of younger people.
A teenager is included in NSW's 27 intensive care patients in NSW, with the majority under 60 and 24 unvaccinated.
Health Minister Greg Hunt pointed to Pfizer supplies as the main reason the vaccine rollout could not be immediately extended to under 40s.
"What we're doing at the moment is following the advice because there are a finite number of vaccines," he told reporters in Melbourne on Tuesday.
"At this point in time we're working through the 40 to 59 age group."
People under 40 are allowed to speak with a doctor about receiving AstraZeneca.
But Australia's expert immunisation panel ATAGI recommends Pfizer for that age group because of an extremely rare side effect.
Mr Hunt said ATAGI would provide advice on expanding the Pfizer rollout to other age groups but noted more vulnerable populations needed to be prioritised.
Just over one million people aged under 40 have so far received their first vaccine dose for a range of special reasons, official figures show.
One million doses of the vaccine landed earlier in the week with similar shipments expected over coming months.
September or October have been raised as potential markers for Pfizer to be extended to under-40s.
The Australian Medical Association's Andrew Miller warned the nation's previous good fortune with coronavirus ending because of new variants.
"Australia's learning now to dance with Delta," he told Sky News.
"We're seeing what it was that caused the fuss around the world and in India and other places where they were sadly overwhelmed."
Dr Miller said vaccines were achieving fabulous results in reducing hospitalisations but tempered expectations about opening up.
"This talk that we can maybe ease up on restrictions when we get to half the population vaccinated unfortunately that's a bit of a dangerous fantasy," he said.
The Perth-based anaesthetist wants Australia to urgently look at vaccinating children aged 12 and over.
He said Delta killed one in 1000 infected children and left six per cent with severe long-term symptoms.
"The fact that COVID can and does kill and disable young people is well known around the world," Dr Miller said.
"Even though it happens more rarely than in nursing homes, this is not a disease of the elderly."
Pfizer has applied for approval to lower the age limit from 16 to 12.
Mr Hunt said the medicines regulator and ATAGI would need to recommend the change before the government made changes.
"If there are two green lights then we will proceed but it's very much a medical consideration."
© AAP 2021