Australia's medicines regulator has concluded that the death of a NSW woman who developed blood clots a day after receiving the AstraZeneca vaccine "is likely to be linked to vaccination".
The Therapeutic Goods Administration's Vaccine Safety Investigation Group drew that conclusion after meeting on Friday night to review a report on the woman.
The AstraZeneca vaccine was last week scrapped as the preferred option for Australians under 50 due to updated medical advice on the risk of a rare blood clotting syndrome.
The 48-year-old woman, who had several chronic health conditions, received the jab after the new advice was shared.
Earlier on Friday the chief medical officer urged the public not to jump to conclusions as the TGA investigated the death.
"The TGA has convened a special expert group to examine the information we have.
"People should be cautious about jumping to conclusions," Professor Paul Kelly told reporters.
On Thursday night the TGA said the woman's death may not be linked to the vaccine.
"It has not yet been established whether there is any link between the COVID-19 vaccine and the tragic death reported by NSW health officials," it said.
Prime Minister Scott Morrison also called for calm, saying concerns around vaccine hesitancy meant it was important that the matter was fully investigated.
Two other people have developed bloods clots likely linked to their AstraZeneca jab in Australia - a woman in Western Australia and a man in Victoria, both aged in their 40s. Both are now recovering.
Prof Kelly confirmed some Australians have been reluctant to receive a vaccine since the medical advice on the AstraZeneca jab was updated.
"We have seen some hesitancy ... particularly in the state-run clinics," he said.
The clinics predominantly deal with health care and quarantine workers, many of whom are under 50.
However, the government's honesty would reassure many, he said.
"One of the crucial components about vaccine hesitancy, or the opposite vaccine certainty, is about understanding and knowing that if there is bad news, it's told."
"That there is openness from people like myself."
That said, the virus itself poses a far greater risk in terms of blood clotting, he said, quoting a new Oxford University study.
The risk of developing blood clots in the brain is eight times more likely after a COVID-19 infection than an AstraZeneca vaccine, it found.
"Clotting is a feature of COVID," Prof Kelly said.
"It also happens to be a feature, very rarely, of the AstraZeneca vaccine.
"But the benefit absolutely, and particularly for those over the age of 50, outweighs significantly the risk."
NSW Premier Gladys Berejiklian on Friday morning said she would still enthusiastically line up for her second AstraZeneca dose.
"The vast majority of our citizens know the benefits of taking a vaccine, they also know the risks, as slight as it is," she told the Nine Network.
"I turned 50 last year and got the jab and am very excited to get the second one. The vast majority of our citizens want a vaccine, want to get ahead of it."
© AAP 2021