Thousands of nurses will strike for 24 hours from 7am on November 23, leaving a skeleton staff in all public hospitals and health services.

It is the fourth such action this year and follows months of drawn out talks between government and union representatives.

NSW Nurses and Midwives' Association general secretary Shaye Candish said calls for safer staffing levels, as well as better pay and working conditions were being ignored.

Despite discussions and efforts by other parties, no real solutions had been offered by the government to address the union's concerns, she said.

"Since our first statewide strike on 15 February, nurses and midwives have gone above and beyond to put patient care ahead of their own basic needs," she said.

"Shift after shift they have continued, burdened by short staffing and constant requests for overtime."

The announcement comes amid a push to legislate nurse-to-patient ratios by Greens MP Cate Faehrmann.

Ms Faehrmann introduced a bill to the NSW Upper House on Wednesday which she says will save lives and help prevent a "mass exodus" of nurses from the health system.

"Chronic understaffing is dangerous for patients and it's dangerous for nurses and midwives," she said.

"This government loves to splash cash on new hospitals but when it comes to ensuring there are enough frontline healthcare workers to actually work in them it cries poor."

The Greens' bill proposes nurse-to-patient ratios be legislated at 1:4 during day shifts and 1:7 on night shifts across general public hospital wards, and 1:3 for emergency departments and 1:1 in intensive care.

A study published in the Lancet medical journal last year found Queensland saved $69 million over two years by introducing similar ratios - more than twice the cost of hiring new staff.

"Queensland, Victoria and the ACT have introduced nurse to patient ratios with the South Australian government committed to doing it in their first term," Ms Faehrmann said.

"There is no reason for NSW not to do the same."

NSW Health Minister Brad Hazzard has been contacted for comment.

Australian Associated Press