Thousands of patients are expected to be impacted when junior doctors walk off the job for 48 hours this month.
All 20 District Health Boards are expected to be affected after the New Zealand Resident Doctors' Association announced a 48-hour strike starting at 7am on October 18.
Senior doctors and around 300 non-unionised staff are expected to try to fill the places left by the 3200 union doctors.
But Ian Powell, the Association of Salaried Medical Specialists's (ASMS) executive director, told Fairfax that during the strike services would be limited to emergency care only.
He said the action would be disruptive for patients and there was no doubt that working doctors "will be under increased pressure".
Powell said operations would only be performed for those patients whose lives were at risk, while elective surgeries would be postponed.
The resident doctors are striking over what they see as unfair and unsafe rosters.
The group representing the DHBs claimed an offer put forward on Monday would have given them "some of the best hours of work in the world". They were disappointed the offer had failed to settle the dispute.
However, Association national secretary Deborah Powell said there was now no alternative.
"It is extremely disappointing it has come to this. However, the DHBs' resistance to meaningfully improve current unsafe rostering practices has left us no choice. We have yet to see sufficient real change in the system after four years of engagement and 10 months of bargaining.
"We see no other way to secure safer rosters for our nation's doctors and the patients we care for."
Junior doctors want to see the number of consecutive night shifts reduced from seven to four and overall consecutive days worked reduced from 12 to 10.
DHB spokeswoman Julie Patterson revealed junior doctors still wanted to be paid for those extra two days off.
"We're not willing to accept a claim that involves an enormous amount more cost, including the RMO's (resident medical officers) being paid for days they're not even working," she told TVNZ.
She has also rejected a survey released by the union claiming doctors are making mistakes at work and falling asleep while driving home, saying the DHBs have been unable to verify the claims.
'We are human. We have limits'
However, one doctor revealed to Fairfax that patients were at risk of misdiagnosis if doctors continued to work such long and tough hours.
The Waikato based doctor described the working conditions, which saw her work on average a 10 to 15-hour day shift for 12 days in a row, as horrendous.
She said she did not enjoy her job and was "tired and tearful" by the time her 12 days were complete.
"I stop caring about my patients and just try to get through the day with minimal interactions."
She said her mental health was suffering as a result.
"We are human. We have limits," she said.
"I wouldn't want to be near my limit looking after someone's family member."