The AstraZeneca coronavirus vaccine is reportedly no longer recommended for people aged under 60 after new expert immunisation panel advice.
Multiple media outlets on Thursday reported the change, which raises the age from 50, the mark set in April after concerns about extremely rare but serious blood clots.
Health Minister Greg Hunt is believed to have received new recommendations from the Australian Technical Advisory Group on Immunisation about the risks of the side effect.
Two people have died in Australia after developing the clotting condition with both in their 50s.
As of last week, more than 3.6 million doses of AstraZeneca have been administered nationwide since the rollout kicked off in Februrary.
Mr Hunt is meeting with state and territory counterparts to discuss the new advice to discuss potential changes to the immunisation program due to the advice.
NSW Premier Gladys Berejiklian told reporters on Thursday she was aware the advisory group had been meeting over the past few days.
"Those experts have the best information," she said.
The 50-year-old premier has had the AstraZeneca jab.
"What is really important is for us to follow the health advice and when I got my vaccine the health advice was and still is that anyone over 50 should go to the GP and get the AstraZeneca."
Australian Associated Press