State premiers have warned against younger people taking the AstraZeneca vaccine despite Scott Morrison making it easier for under-60s to access it.

The man responsible for providing official expert advice on vaccines has sought to clear up confusion around who should receive the Pfizer and AstraZeneca jabs.

A bitter spat has broken out between politicians and health officials over the coronavirus vaccine rollout.

The mangled messaging has fuelled fear and confusion over who should get what vaccine.

On Monday, Prime Minister Scott Morrison said people under 40 could talk to their GP about getting the AstraZeneca jab.

Mr Morrison provided GPs legal protection to vaccinate all adults and offered patients Medicare cover for their consultations.

But several state premiers and their medical advisers have pushed back against his advice.

Christopher Blyth, who co-chairs the Australian Technical Advisory Group on Immunisation, said people under 60 should get the Pfizer vaccine.

Professor Blyth said people in that age group should only be considering AstraZeneca in "pressing" circumstances.

"There are some situations where that would be warranted, but they are quite small," he told ABC radio on Thursday.

"The ATAGI advice is that Pfizer is our preference for those under the age of 60 years."

The preference for the Pfizer vaccine to be given to Australians aged under 60 followed the AstraZeneca shot being linked to a small number of rare blood clots.

Professor Blyth refused to be drawn on whether he was frustrated with the public messaging and ensuing political battle.

"I'm not going to focus on the politics of this," he said.

"Our role is to give health advice to government, and that's what we're going to focus on."

Queensland Chief Health Officer Jeannette Young has declared she does not want people under 40 to receive AstraZeneca.

"I don't want an 18-year-old in Queensland dying from a clotting illness who, if they got COVID probably wouldn't die," Dr Young said on Wednesday.

However, other medical professionals have distanced themselves from her remarks.

Australian Medical Association vice president Chris Moy described her comments as concerning and inappropriate.

"As a doctor my job is to offer an opinion and to offer treatments of medical benefit, it's not to deliver things as an edict," Dr Moy told the ABC.

West Australian Premier Mark McGowan wants people in his state to follow ATAGI's advice.

"That is the advice we have and that is the national advice from the immunisation experts," he said.

"Clearly, the Commonwealth has taken a different approach."

Victorian Health Minister Martin Foley said his department had received confirmation of a change in Commonwealth policy to expand the vaccine rollout.

"The last thing we need is confusion around vaccines. What we need is certainty and consistency and confidence in the vaccination program," he said.

Australian Medical Association president Omar Khorshid said the federal-state spilt was causing confusion.

"Unfortunately, the prime minister's thrown a little bit of a hand grenade into our vaccine program," he told Sky News.

As well as shining a light on the bungled vaccine rollout, outbreaks of the highly contagious Delta strain have forced harsh restrictions across the country.

More than 12 million people are locked down across Queensland, the Northern Territory, Western Australia and NSW.