Pay rates for senior doctors covering their junior colleagues who will be striking next week are in dispute.
The Association of Salaried Medical Specialists says District Health Boards have broken off discussions with it over the pay rates for extra work by senior doctors during the 48-hour strike by junior doctors from 7am on Tuesday.
About 90 percent of all specialists and senior medical and dental officers working in public hospitals are members of ASMS.
The ASMS wants rates in a 2008 agreement, when junior doctors last went on strike, with increases for inflation since. The DHBs suggested 28 to 33 percent below the 2008 level.
The ASMS said it was willing to negotiate but the DHBs decided to unilaterally set a range of rates from DHB to DHB, marginalising it.
The ASMS has put out advice to its members on rates:
In 2008 some senior doctors donated the extra pay they received to charities.
DHBs reported extra costs for senior doctors of several hundreds of thousands of dollars, partially offset by savings from not paying junior doctors.
Junior doctors want an extra two days off, but they want to be paid for them.
All 20 DHBs are expected to be affected by the strike by 3200 junior doctors.
Canterbury DHB said on Friday it employs about 490 resident medical officers and about 70 percent are members of the New Zealand Resident Doctors' Association, which has organised the strike.
It has been planning to ensure safe care during the strike.
The emergency department at the hospital will remain open but hundreds of outpatient appointments and about 150 elective surgeries are being rescheduled.