Advice given by the NSW chief health officer before changes were made to COVID-19 pandemic restrictions will remain secret until parliament orders its release.

Premier Dominic Perrottet told a budget estimates hearing on Thursday that advice given by Kerry Chant is cabinet-in-confidence.

Throughout the pandemic the government has received health advice to inform its decisions.

"We would balance that advice with other concerns and other issues facing the state," Mr Perrottet said.

"There's a whole array of perspectives that come into the decision-making process," Mr Perrottet said.

The premier on Wednesday announced home isolation for close contacts, hotel quarantine and social-distancing requirements on public transport will be dropped from 6pm on Friday.

Hotel quarantine for unvaccinated international returning travellers will also end on April 30.

Dr Chant's advice on those matters remains confidential.

Greens MP Cate Faehrmann asked why the advice should be kept from the public.

"Well it will probably end up in an SO-52 at some stage, won't it?" Mr Perrottet replied.

Under standing order 52, the NSW upper house can require the government to produce documents relating to matters of public interest.

Mr Perrottet said the point of cabinet confidence was to ensure public servants could deliver frank and fearless advice to inform decisions and releasing the information would undermine the process.

No public health officials had recommended any further expansion of face mask mandates, he said.

Potential changes to vaccine mandates in some sectors, based on risk assessments, were also flagged on Wednesday.

Aged care and disability workers will still need to be vaccinated but others such as teachers and police officers may no longer require vaccinations depending on the assessed risk of their roles.

One Nation MP Mark Latham asked when school staff who had been stood down because they were not vaccinated would be back in classrooms, amid a shortage of teachers.

Mr Perrottet said he had asked ministers to make sure those risk assessments were conducted immediately.

In the past 24-hours NSW recorded 17,447 new COVID-19 cases and 16 more deaths.