Story by Rowan Quinn of RNZ
About half the country's junior doctors are set to walk off the job for 25 hours with every aspect of the hospital system likely to be affected.
Te Whatu Ora says emergency departments will remain open and patients should turn up to their regular appointments unless they hear otherwise.
About 2500 junior doctors are due to walk off the job from 7am on Tuesday to 8am on Wednesday.
Christchurch Hospital has said it might have to postpone treatment for some patients, saying it would contact them directly.
That would likely be the case in some other hospitals, but Te Whatu Ora chief of people Andrew Slater said the agency would not know the full impact until after the strike had finished.
Health services would still be available for those who needed them, he said.
Senior doctors and junior doctors from the other main union would still be working, and would be providing essential "life preserving" services.
The doctors taking industrial action are members of the Resident Doctors Association.
Senior advocate Melissa Dobbyn said they worked right across the country and in every speciality.
They range from those just out of medical school, to those about to become specialists.
Most were due for a pay rise of about 20 percent in their latest contract, but said they were striking to support a smaller group in line for a pay cut.
One of the doctors, Dr Rosa Tobin Stickings told First Up the current pay offer was not good enough and they couldn't accept pay cuts for any union members.
Tobin-Stickings who is training to be an emergency registrar said with 500 resident doctors short across the country, shifts were getting "harder and harder".
It was not unusual to start work and be told she had to cover for another doctor.
"It's exhausting to be working in this environment and we've been working in this environment for some years ... and we're getting pretty burnt out."
Sometimes, the doctors had to apply for annual leave a year in advance and it was difficult to get leave for education puposes or to attend conferences to help with their training.
Many junior doctors had enormous leave balances and so far Te Whatu Ora had not responded to how leave pressures could be improved, she said
A second two-day strike is planned from 16 May, and the union would take a vote on further action, Dobbyn said.
RNZ