Thousands of appointments and non-emergency surgeries have been postponed as a second strike by junior doctors starts on Tuesday morning.
The doctors are pushing for changes to their employment agreement, saying they're working unsafe hours.
The 73-hour strike is expected to affect 18 district health boards across the country when it kicks off at 7am on Tuesday and runs until 8am on Friday.
National contingency planner Anne Aitcheson says it shouldn't mean longer waits for patients.
"The number of people with less urgent care needs are likely to have those needs met by their GP, so waiting time is always an issue, we don't expect it to be any worse."
Ms Aitcheson says if people are sick, they should go to their GP or emergency department.
Canterbury DHB chief executive David Meates says emergency care is still available.
"Any acute or urgent care - those services will be all functioning and operating. Largely what we're looking at is care which is able to be deferred, we're looking at deferring."
Mr Meates says Canterbury has postponed 500-600 non-urgent surgeries, appointments and procedures.
The New Zealand Resident Doctors' Association says the dispute is being prolonged by DHB bosses sending representatives to negotiations, instead of attending themselves.
The people chief executives send to the meetings cannot make agreements, which makes it very hard to reach a settlement, the association says.
"This has previously resulted in what looks like a possible settlement at the table, being rejected by the CEOs, a step backwards in bargaining, and prolonging of the dispute," The NZRDA said in a statement on Saturday.
"The CEOs were not able to make themselves available to discuss more recent discussions until the end of next week."