"It's pretty simple," NSW Health Minister Brad Hazzard told reporters on Wednesday.
"If you don't care enough to get vaccinated and look after your colleagues, if you don't care enough about your patient, you probably shouldn't be in the health system."
Mr Hazzard said he expected that number to keep rising.
It comes as NSW hospitals come under increased strain and ahead of an anticipated "exit wave" expected to see COVID-19 case numbers rise again once lockdowns end.
Premier Gladys Berejiklian has repeatedly warned that October will be the worst month for the state's hospitals.
NSW Nurses and Midwives’ Association general secretary Brett Holmes said a reduction in staff, however small, will take a toll.
"Overall, there will be a relatively small level of impact. But no doubt, wherever we lose a nurse from the floor, that will have an impact," he told SBS News.
Mr Holmes said while there were issues with access to the vaccine at the beginning of the rollout, particularly in regional areas, they have now been "mostly addressed".
"We're not getting feedback from the members that the reason for not being vaccinated is access to the vaccines," he said.
He said there has now been "sufficient time for people to make up their mind about getting vaccinated", but it was never too late for health workers to get the jab.
"We really continue to encourage those nurses to reconsider their decision and get vaccinated. We need them at the bedside. We need them in the workforce," he said.
'Very small' number of healthcare workers still to be vaccinated as deadline looms
Thursday also marks the first deadline for Queensland Health staff who care for patients to have had one dose of a COVID-19 vaccine.
The mandate requires them to be fully vaccinated by 31 October.
Queensland Health says more than 91 per cent of almost 115,000 workers at the state's hospital and health services - some 105,000 workers - have already had one dose. More than 83 per cent - around 95,000 - are fully vaccinated, it says.
Health Minister Yvette D'Ath said on Wednesday it's not uncommon for health workers to be required to have certain vaccines.
"We require our health workers to get vaccinated for a range of immunisations. This is about keeping them safe, their work colleagues' safety, [as well as] every patient and visitor that walks into their hospital and their own family members," she told reporters.
Western Australia is adopting a staged vaccination approach with tier one facilities, such as COVID-19 wards, off-limits for the unvaccinated from October and one dose required to enter all health facilities by December.
Victoria, meanwhile, has set a 15 October deadline for health care workers to be vaccinated.
Australia is joining other nations in making vaccines compulsory among health workers.
On Monday, a mandate went into full effect in New York. Hospitals have now begun firing or suspending unvaccinated employees, resulting in staff shortages.
A series of wider protests against vaccine mandates and passports in New York have also been staged this week.