Nurses across the country have confirmed a notice of a 24-hour strike, starting on 5 July.
District Health Boards (DHB) were working on contingency plans following a notice to strike by the New Zealand Nurses Organisation.
Nurses covered by the New Zealand Nurses Organisation (NZNO) collective agreement had issued a notice for a full strike.
The nurses are planning to strike from 7am on 5 July, and are expected to give notice next week if they will strike again on 12 July.
This followed nurses' rejection of a new pay deal from DHBs - which included pay rises of 9 percent over the next 15 months, with some eligible for a 15 percent increase.
The offer included a one-off payment of $2000, a 2 percent increase in staffing, as well as two new steps on the pay scale.
DHB spokesperson Helen Mason said the boards were doing all they could to settle the agreement and avoid the strikes.
"We're in mediation with the NZNO on Friday and in the interim, DHBs will start implementing contingency plans to ensure the safety of patients and staff," she said.
"We are extremely concerned about the threat of industrial action and working hard to find a solution."
Plans were being made to make sure patients and staff would be safe during the industrial action.
That meant "significant changes" to normal services.
"DHBs are working closely with the NZNO to ensure emergency and essential services will be available," Ms Mason said.
"Each DHB will be in touch with their affected patients to provide more information on this."
During the day of the planned strike, people should not delay seeking medical treatment or going to hospital if the matter is urgent. They should dial 111 for emergencies or an ambulance.
They can visit their GP or a local pharmacy, or call Healthline on 0800 611 116.