Hundreds of public school workers in NSW tested positive to coronavirus this week, but the government has heralded the school return as a "major achievement".

Premier Dominic Perrottet says he wants to focus on "the positive" after people said returning children to classrooms "couldn't be done".

"What I saw this week was smiles on so many kids' faces right across the state as they returned back to class. We had a plan, we've resourced that plan, we executed that plan," Mr Perrottet said.

Some 86 per cent of school children were back in classrooms this week, Education Minister Sarah Mitchell said on Friday.

While 617 staff across 438 schools tested positive for COVID-19, Ms Mitchell said casual teachers and existing staff had been able to cover for them.

More than 2400 primary and secondary students also tested positive this week.

The education department is distributing 17.5 million more rapid antigen tests to maintain testing protocols in the third and fourth week of term.

Teachers Federation NSW president Angelo Gavrielatos says the tests "represent an important line of defence".

"There's no doubt that the rapid antigen testing is identifying people who would otherwise be in schools infected," he told AAP on Friday.

The more than 3000 cases recorded in schools this week shows the importance of implementing risk mitigation strategies like continued mask wearing and surveillance testing, Mr Gavrielatos says.

But teachers are bracing for what the number of furloughed staff might look like after the weekend.

NSW is facing "the clashing of two crises": One being COVID-19 and the other a teacher shortage that Mr Gavrielatos said the government has neglected to act upon satisfactorily for more than two years.

"The crisis in teacher shortages was a problem well before the Omicron outbreak, well before COVID-19," Opposition education spokeswoman Prue Car said on Friday.

She says the premier has not done enough to address the shortage despite it being "at crisis levels for many years", exacerbating the problem of hundreds of teachers testing positive in the first week of term.

Ms Car said while everyone agrees children need to be in the classroom learning, "every teacher that's not in the classroom means that classes have to merge and the children in classrooms are impacted by the shortages".

Some 41.6 per cent of NSW's primary school-aged children have received at least one vaccine dose, while 42.8 per cent have received a booster (or top-up for immunocompromised people).

Those aged 16 and 17 are now eligible for boosters in NSW health clinics, following the advice of the Australian Technical Advisory Group on Immunisation.

NSW recorded 10,698 new coronavirus cases and 31 deaths on Friday amid signs of a stabilising outbreak as more health staff return to work.

Hospitalisations fell to 2494 on Friday while ICU admissions remained at 160, with 75 now on ventilators, an increase of seven on the previous day.

Mr Perrottet says hospitals are operating "well within capacity", allowing elective surgery to resume in private hospitals and non-metropolitan public hospitals from Monday.

Chief Health Officer Kerry Chant said it was pleasing to see hospitalisations and ICU admissions decrease, but people on ventilators remained at "a more constant level".

"We expect that to be a little bit slower in declining because a number of the patients have got longer length of stays in ICU when they are ventilated, but we will see that number come down as well," Dr Chant said.