NSW will roll out Pfizer-produced COVID-19 vaccinations for children between five and 11 years from next week.

The vaccine is a special formulation and will be delivered in doses small enough to generate an immune response that's as strong as a full adult dose.

The children will be given two doses eight weeks apart with the aim of preventing them from developing severe illness or transmitting the virus to another person.

"We know it's safe," NSW Chief Paediatrician Matthew O'Meara said on Wednesday.

"It's been tested in thousands of children in clinical trials and millions of doses of first and second doses have been given in other countries."

Dr O'Meara said any side effects were minor.

"Many kids complain about a bit of a sore arm for a day or two afterwards," he said.

"But the headache, muscle ache, fever, chills and nausea ... is pretty uncommon in children and can be managed with the usual pain-relieving medications."

Dr O'Meara acknowledged parents may be weighing up the risks and benefits of giving a young child a vaccine but stressed COVID-19 was usually mild in children.

"In fact, many children will have no symptoms at all and a large number will have mild symptoms of a cough, cold, runny nose and fever that lasts up to five days."

But some children can become seriously ill and require hospitalisation if they aren't vaccinated. About one or two in every 100 would need to go to hospital and one in 1000 would end up in intensive care.

"We expect those numbers to be lower with the Omicron strain but it's still not an entirely benign disease," Dr O'Meara said.

Premier Dominic Premier says the rollout will ensure schools open on time for the first day of the new term in 2022.

"We want a seamless transition back into the school year," he added.

Currently, vaccinations are offered to children aged 12 to 15 and so far 81.4 per cent have had their first dose and 78 per cent have had two.

In the 16 years and older cohort - which includes adults - 95 per cent have had one dose and 93.6 per cent have had two.

NSW Health Deputy Secretary Susan Pearce said the vaccine take-up in the 12-15 years group had been "really rapid" and she'd like to see the same again in the five- to 11-year-old cohort.