Vulnerable communities across NSW can access 10 free rapid antigen tests over three months, with the state expanding its concession program as COVID-19 cases surge.

The government will provide free RATs to vulnerable communities by expanding its existing program to include those accessing tests through the federal government's Concessional Access Program.

The scheme, which provides free tests to concession card holders, is due to expire at the end of the month.

It comes as NSW schools return on Monday with principals given a range of measures to curb cases as a new wave emerges.

Premier Dominic Perrottet said his government is committed to leaving no one behind through winter.

"We want to make sure that our vulnerable communities have access to these tests," he told reporters on Friday.

"We know they work, we know that they make a real difference and are a crucial part of everyone taking that responsibility as we move through this next phase of COVID."

"(The virus) is not going away and that means we have to keep taking personal responsibility."

The premier also urged residents to take up their flu and COVID-19 booster shots.

"There's a broader responsibility we have, and that's to ... ease the pressure on the health system here in our state and around the country," he said.

Mandating masks, banning big gatherings and axing assemblies are some of the options on the table for schools to control case numbers.

Teachers in NSW have taken 30 per cent more sick days as the state and federal governments continue to wind back health restrictions and support systems.

Education Minister Sarah Mitchell pointed to schools experiencing a double whammy of coronavirus and flu.

"We are absolutely feeling the pressure ... in our schools , there's no question of that," she said on Friday.

"(People) know what they need to do now in terms of living with COVID in our schools. But we're in winter and we know that term three will probably have some bumps along the way."

Schools that experience large outbreaks will move to limit assemblies and large gatherings.

Mask mandates could also return however health authorities are still recommending rather than mandating mask wearing.

Chief Health Officer Kerry Chant said messaging around health measures has changed as authorities gained a better understanding of the virus.

"We have responded to the evidence changing, we need to re-communicate those messages and build an understanding in the community," Dr Chant told ABC News on Friday.

"The reason we are changing those messages is not because we got it wrong at one point in time, but in fact because the evidence has evolved, or in the case of Omicron, the virus has changed," she said.

Minister for Multiculturalism Mark Coure said the expanded program would allow eligible concession card holders to access 10 RATs over the three months up to October 31.

"There is no need to rush or panic about whether or not you will be able to access tests. We have enough tests to support you," he said in a statement.

Vulnerable communities eligible for free tests include people with disability and their carers, homelessness services, social housing tenants, multicultural groups as well as children and young people in out-of-home care.

Tests will be available through 210 neighbourhood and community centres across the state.