The move comes as more than 35,000 children received their first vaccination on the first day of the primary rollout for five- to 11-year-olds on Monday.

While the number of people becoming immunised with booster shots continues to grow, the third shots are currently only available for those 18 and older.

A federal health department spokesman said it was working to support applications for child boosters once data became available.

"The Therapeutic Goods Administration is evaluating data on the Pfizer ... booster for individuals aged 16 to 17 years of age," the spokesman told AAP.

"The Australian government continues to encourage individuals to complete a two-dose vaccination schedule, as this enables strong protection against severe illness and hospitalisation."

The country's leading immunisation group is providing advice to the government on whether a booster is required for under 18s and how often it should be administered, should it be approved.

Meanwhile, Deputy Chief Medical Officer Dr Michael Kidd expects there would be a reduction of outbreaks in schools following the start of the child vaccination rollout.

Dr Kidd said more appointments would become available in coming weeks, with the number of vaccination sites nationwide increasing from 6000 to 8000.

"We have enough of the Pfizer vaccine for every five- to 11-year-old to receive their first dose by the end of this month," he told the ABC.

"By the time children are returning to school the majority of children in Australia will have had the opportunity to have had their first dose."

Despite the large numbers of child vaccines administered, many have reported difficulties in securing appointments, or having them cancelled due to vaccines not arriving on time.

Opposition Leader Anthony Albanese said the situation was also impacting on the rollout of the booster program.

"Why is it that people are having to make calls trying to search somewhere to get a booster shot into the third year of this pandemic, or trying to get their children vaccinated?" he said.

"If you have appointments which are made and then delayed, that just adds to the issue out there of lowering vaccination rates."

Prime Minister Scott Morrison said talks were ongoing about how a return to school across the country could be carried out safely in the wake of the Omicron variant.

Meanwhile, unions have called for an urgent meeting with the government to discuss the impact of the spread of Omicron on exhausted essential workers.

Australian Council of Trade Unions Secretary Sally McManus wrote to Mr Morrison with a list of demands warning an "unofficial lockdown" was hurting affected workers.

"The prime minister has not heard from working people and we are on the front lines," Ms McManus said in a statement.

"Australian workers are not OK at the moment. We have never had so many working people sick at once."

More than 90,000 cases were reported nationally on Tuesday.

In NSW there were 25,870 new cases along with 11 deaths, while Victoria registered 37,994 cases and 13 deaths.

A new fatality was recorded in Queensland, as the state notched up 20,566 cases, with Tasmania announcing 1379 new cases.

There was one new death in the ACT, with a record 1508 infections in the national capital, while there were 2921 cases in South Australia and 594 in the Northern Territory.

Australia on Monday surpassed more than one million total cases since the pandemic began two years ago.

Australian Associated Press