Scott Morrison has appealed for Australia's expert immunisation panel to change its AstraZeneca vaccine age recommendation.
But the prime minister insists he is following senior scientists' advice despite lobbying for changes from the Australian Technical Advisory Group on Immunisation.
ATAGI recommends the jab should be administered on people over 60 because of a link to extremely rare but serious blood clots.
The prime minister blamed the recommendation for causing a "big problem" that further slowed down his government's bungled vaccine rollout.
He has now revealed making a "constant appeal" to ATAGI for changed recommendations.
"The situation Australia faces should be managed on the balance of risk, as ATAGI has said to me in the past," Mr Morrison told reporters in Canberra on Wednesday.
The prime minister was accused of throwing a hand grenade into the rollout when he encouraged people under 40 to speak to their doctor about receiving AstraZeneca.
About 32,000 people in the age bracket have received that jab since he made the comments in an evening news conference.
A late-night announcement was also used to reveal ATAGI changed its AstraZeneca recommendation from 50 and above to over-60s.
Mr Morrison became defensive when asked if the government's confusing AstraZenca messages led to increased vaccine hesitancy.
"I cannot control what ATAGI advises," he said.
He said the suggestion implied the government should have refused medical advice despite his appeals for the recommendation to be reconsidered.
Senior Labor frontbencher Tony Burke said the prime minister risked a perception he was pressuring the expert immunisation panel.
Mr Burke said independent institutions were critical to public confidence in vaccines.
"We undermine the independence of ATAGI at out peril," he told Sky News.
The prime minister also refused to apologise for the bungled rollout and denied it was to blame for lockdowns affecting more than half of Australia's population.
"Australians just want us to get it right," he said.
"No country has got their pandemic response 100 per cent, I think Australians understand that."
Just 14.5 per cent of the population is fully vaccinated, with the nation lagging behind most of the developed world.
The government has come under fire for heavily relying on AstraZeneca with supplies of Pfizer taking months to ramp up.
Mr Morrison acknowledged the rollout had significant challenges but pointed to a range of factors behind delays.
"I take responsibility for the problems that we have had, but I am also taking responsibility for the solutions we're putting in place and the vaccination rates that we are now achieving," he said.
One million doses have been administered over the past week including more than 174,000 in the past 24 hours.
Opposition Leader Anthony Albanese said the prime minister was wrong to declare the vaccine rollout was not a race.
"We see now the consequences of the fact that we're running last in the race to get people vaccinated in the developed world," he told ABC radio.
Australian Associated Press