The Australian Technical Advisory Group on Immunisation gave the final green light for the vaccine to be rolled out across the country.
Health Minister Greg Hunt said the new approval would help to boost Australia's child vaccination rate, which now stands at nearly 50 per cent.
"We have Moderna in over 4000 points of presence around the country," Mr Hunt told reporters in Canberra.
"That will make it very easy for parents."
The dose for children will be half of what is given to adults, but is the same amount as a Moderna booster shot.
The Therapeutic Goods Administration has recommended children receive two doses of the Moderna vaccine, spaced eight weeks apart.
However, it can be administered as little as four weeks apart in some instances, such as if a child is immunocompromised.
The head of the administration, Professor John Skerritt, said the TGA was the first major regulator in the world to approve the Moderna vaccine for use in children.
"We do expect other global regulators to follow soon," he told reporters.
"There's a convenience factor in that the GP or a pharmacy or vaccination centre can use exactly the same vials from Moderna for children, for boosters and for the adults."
Mr Hunt said the number of parents who intended to have their children be vaccinated against COVID had risen to 76 per cent.
It comes as the health minister asked infectious diseases expert Professor Julie Leask to lead a roundtable on what can be done to boost vaccine rates among children.
The task force, which will meet next week with the Commonwealth, state and territories, will also look at whether schools could be used as part of vaccination drives for children.
Mr Hunt said while the number of children who have been vaccinated is already high, it could go even further.
"Through the program, I have not put a ceiling or floor on the numbers (of child vaccination), and that's hopefully helped us to continue to drive up and up," he said.
"With children's vaccination programs, we're encouraging all states and territories to undertake this."
Mr Hunt also revealed since the Novavax vaccine was approved in Australia last month, 12,000 doses of the protein-based vaccine have been administered across the country.
"(The rate is) well ahead of what we'd anticipated in this time frame," he said.
"That's providing an additional option for people who, whatever their circumstances, may not have been confident or may not have been able to have taken one orf the other vaccine options that's available."
National booster rates have risen to 62.1 per cent of the eligible population.
Wednesday saw 60 COVID-19 deaths reported across the country, including 37 in Queensland, 17 in Victoria and six in NSW.
Nationally, there have been more than 23,000 COVID-19 cases registered in the past reporting period.