The medicines regulator has given provisional approval to a Pfizer COVID-19 vaccine booster for children aged five to 11.

However the Therapeutic Goods Administration (TGA) said on Wednesday the government's decision on the use of this vaccine as a booster in this age group would be informed by advice from the Australian Technical Advisory Group on Immunisation (ATAGI).

At its most recent meeting, ATAGI considered evidence in relation to the Pfizer booster for five to 11 year olds, including disease burden, durability of protection against infection and severe disease, safety and international recommendations.

It said if the TGA registered the booster dose, it would make recommendations.

Children aged five to 11 years are currently recommended to have a primary course - two doses for most people - of a COVID-19 vaccine.

Meanwhile, with commuters almost Australia-wide no longer required to wear masks on public transport, doctors warn ditching the mandate will have consequences.

On Wednesday, NSW and Queensland join South Australia, WA, Tasmania and the NT in not requiring passengers on public transport to mask up.

Victoria will follow suit at midnight on Thursday while masks remain mandatory on public transport for people aged 12 and older in the ACT.

NSW Premier Dominic Perrottet said removing the mask mandate was a common-sense approach, bringing the rules into line for people travelling on buses, trains, ride-share vehicles, taxis and planes.

NSW Health still recommends people wear masks where they cannot physically distance and in settings where there are vulnerable people.

Queensland Health Minister Yvette D'Ath is asking commuters to wear masks when appropriate.

"There are still directions. If you are someone who has been isolating, after your five days you are requested to wear masks," she said.

Australian Medical Association president Steve Robson said governments continued to make serious decisions with no consultation and no discussion.

"This is a major decision which will have consequences, and it should have been done with national consensus and clear health guidance," he said.

"Masks kept us safe from infection when we didn't have a vaccine, and they continue to be an effective, low-cost, low-hassle and proven way to protect ourselves and others."

Prof Robson said COVID-19 was still very serious, particularly for vulnerable populations, and was deadly for many people.

"Restrictions are being loosened, including time in isolation, and we still don't have any sign this was based on medical evidence," he said.

Prof Robson said the decision came at a time when worrying data was still being released, including in relation to aged care.

"Many of our most vulnerable people in the community are the ones that use public transport the most,'' he said.

"Masks are the last of the sensible protections, and we urge people not to abandon using them."

Federal Assistant Health Minister Ged Kearney has also announced investment in a new study into COVID vaccinations and infection in children and people with chronic diseases.

Ms Kearney says there is a research gap about the impact of the virus on vulnerable groups.

"This research will ultimately help to improve the care that children and adults receive, who are at a higher risk of becoming seriously ill from COVID," she said.

The study will be undertaken by Monash University.

© AAP 2022

A school bus had been slowing down to avoid a crash when a truck hit it from behind, forcing it down an embankment on a highway west of Melbourne.

Two teenage girls and two adults were seriously injured in the accident on the Western Highway at Bacchus Marsh in the early hours of Wednesday morning.

The school bus was carrying four adults and 27 students in years nine to 11 from Ballarat's Loreto College to the airport for a trip.

VicRoads were clearing a crash from earlier in the night when the truck collided with the bus, police said.

"Quite miraculously, they've self-evacuated and other people, I believe truck drivers and that, stopped to assist them," Detective Inspector Roger Schranz told reporters on Wednesday.

"I would have assumed someone would have passed away out of this entire tragedy. So they're all very fortunate people."

Two teenage girls were flown to the Royal Children's Hospital in a serious but stable condition.

A woman in her 40s and a man in his 50s were taken to the Royal Melbourne in a serious but stable condition.

18 others were taken to various hospitals in a stable condition.

Police will investigate whether drugs, alcohol or speed were factors in the crash.

Melbourne-bound highway lanes are expected to be closed for the rest of the day as investigators analyse the scene.

The students' parents were asked to stay away from the crash and contact Ballarat police station.

Nearby resident Ange Greenland woke to the sound of the air ambulance arriving.

She told AAP the crash site was "pretty nasty" and it was distressing that the young girls had to walk up the embankment after the crash.

"They walked up the off ramp to a waiting bus half a kilometre away," she said.

"I really was very angry because I thought if that was mine, if it was my child ... I could not believe how they were treated".

In a statement the school thanked emergency services for coordinating care and providing triage at the scene.

"Our caring Loreto community has deep concern for the injured and their families and we ask for their privacy to be respected," it said.

© AAP 2022

A school bus had been slowing down to avoid a crash when a truck hit it from behind, forcing it down an embankment on a highway west of Melbourne.

A teenage girl and a driver were seriously injured in the accident on the Western Highway at Bacchus Marsh in the early hours of Wednesday morning.

The school bus was carrying four adults and 27 students in years nine to 11 from Ballarat's Loreto College to the airport for a trip.

VicRoads were clearing a crash from earlier in the night when the truck collided with the bus, police said.

"Quite miraculously, they've self-evacuated and other people, I believe truck drivers and that, stopped to assist them," Detective Inspector Roger Schranz told reporters on Wednesday.

"I would have assumed someone would have passed away out of this entire tragedy. So they're all very fortunate people."

One of the teenage girls was flown to the Royal Children's Hospital with lower body injuries in a serious but stable condition.

Another girl was taken by air ambulance to the Royal Melbourne Hospital. She was in a stable condition with upper body injuries.

A woman in her 40s and a man in his 50s were also flown to the Royal Melbourne in a stable condition.

Police will investigate whether drugs, alcohol or speed were factors in the crash.

Melbourne-bound highway lanes are expected to be closed for the rest of the day as investigators analyse the scene.

The students' parents were asked to stay away from the crash and contact Ballarat police station.

Nearby resident Ange Greenland woke to the sound of the air ambulance arriving.

She told AAP the crash site was "pretty nasty" and it was distressing that the young girls had to walk up the embankment after the crash.

"They walked up the off ramp to a waiting bus half a kilometre away," she said.

"I really was very angry because I thought if that was mine, if it was my child ... I could not believe how they were treated".

In a statement the school thanked emergency services for coordinating care and providing triage at the scene.

"Our caring Loreto community has deep concern for the injured and their families and we ask for their privacy to be respected," it said.

© AAP 2022

Swift action has been taken against two senior staff members at Queensland's forensic lab as work continues to retest thousands of DNA samples that were initially overlooked.

An interim report handed down on Tuesday exposed serious shortfalls that centre on a failure to test samples under a certain DNA threshold.

Some samples could provide partial or complete DNA profiles, and Queensland police are reviewing criminal cases potentially affected between 2018 and June 2022.

It is still unclear why the threshold limits were changed.

Premier Annastacia Palaszczuk confirmed the staff members had been stood down pending the full results of an inquiry.

"This is perhaps one of the most concerning reports that our state has seen and we need to get to the bottom of it," she told reporters on Wednesday.

Ms Palaszczuk did not say why the staff members stood down or their positions.

"All I know is that the Director-General has stood two people down in the forensic unit pending the outcome of the inquiry," she said.

The premier said there was no advice or evidence of ministerial involvement in decisions about threshold limits.

"We want to get to the bottom of this, we want to know who was responsible, we want justice for victims. That is paramount," Ms Palaszczuk said.

Opposition leader David Crisafulli called for an apology to be issued to all Queenslanders.

"I don't think we as a state can comprehend just how big this report is and the ramifications of it. It will stretch for many years to come," he warned.

"I have no doubt as a result of these failings, victims were denied justice and criminals are walking the street, and every Queenslander is owed an apology for the failings that the state government has overseen."

Experts fear the findings may erode community trust in the science of DNA as a reliable source of evidence.

"DNA has the power to exonerate as well as convict. When the science is not practised correctly when the expert makes a statement which is beyond their expertise, lives can be destroyed," said forensic scientist Dr Richard Matthews.

"The innocent will be imprisoned, and the guilty will walk free. Resources of the state will be wasted."

The findings highlight the need for greater scrutiny and overarching regulation of expert witness evidence in Australia, he said.

"The science must be practised correctly with correct quality assurance measures in place. Laboratories should be independently accredited," Dr Matthews said.

A meeting between the premier's Director-General Rachel Hunter, the police commissioner and the heads of the Justice and Health department will be held on Wednesday to act on findings in the interim report.

The Commission of Inquiry into Forensic DNA Testing in Queensland will hold public hearings from next Monday.

The full report is due in December.

© AAP 2022