The prime minister is urging the Australian Technical Advisory Group on Immunisation to recommend the jab to people under 60.
Pfizer remains the preferred coronavirus vaccine for that age group.
ATAGI is advising the risks of extremely rare blood clots outweigh the benefits of AstraZeneca for under 60s.
But Morrison believes coronavirus outbreaks across NSW, Victoria and South Australia have changed the equation.
“When COVID cases are rising, that means people have a greater likelihood of catching COVID, particularly older people, then the balance or risk changes,” he told 4BC radio on Thursday.
“I have just simply said ‘the balance of risk is changing guys, so how is that impacting on your advice’ and it’s time to think about that.”
ATAGI provides scientific advice on immunisations once medicines are approved for use.
The prime minister has revealed he is constantly appealing with the panel to update its AstraZeneca advice.
Australia has ample supplies of AstraZeneca, which is produced in Melbourne, but there not yet enough Pfizer imports are arriving to vaccinate people under 40.
Labor’s health spokesman Mark Butler agreed with the Australian Medical Association that the prime minister had put unfair pressure on ATAGI.
“This is the prime minister using the power of his office, as the head of the country, trying to shelve responsibility for the terrible failures of this vaccine rollout onto them,” he said.
Professor Allen Cheng, the co-chair of the expert immunisation panel, released a statement after Mr Morrison’s initial comments.
He said the panel met weekly to assess safety data and local case numbers when considering risk-benefit assessments for the AstraZeneca jab.
ATAGI’s latest advice said people under 60 in outbreak areas should reassess whether to receive AstraZeneca given greater benefits.
Just 14 per cent of Australians aged over 16 have been fully vaccinated almost five months after the rollout began.
The prime minister has repeatedly refused to apologise for the program’s problems but acknowledged delays were regrettable.
Sydney is in the grips of a outbreak that has plunged large parts of the state into lockdown.
More than 500,000 people in Sydney lockdown areas have applied for disaster payments, with their claims totalling $245 million.
Victoria and South Australia are also locked down, with the contagious Delta variant also circulating in Melbourne and Adelaide at lower levels.
Claims will open for affected Victorians on Friday, while South Australians must wait until next week.Jump to next article