The union wants rosters of seven nights in a row replaced with a maximum of four nights in a row followed by three days off. It also wants 12 days on/two days off rosters replaced by 10 days on/four days off.
The 20 district health boards have offered to split night shifts causing fatigue and reduce the maximum number of days worked in a row to 10. But they say the union wants members paid for the days off resulting from the changes.
Senior doctors will be at the forefront in helping to maintain public hospital healthcare during the strike by their resident-doctor colleagues in a fortnight.
Resident doctors - junior house officers through to senior trainee specialists - are at the core of public hospital healthcare and more than 3000 in the Resident Doctors Association will strike for 48 hours starting at 7am on October 18.
District Health Boards' spokeswoman Julie Patterson said senior doctors would be among those asked to help fill gaps created by the strike.
"Those that we will be asking will be from across professional groups and not just senior doctors. It's going to be very variable depending on union coverage within each hospital."
DHBs would set up a national coordination centre to oversee strike-related issues and would today send a series of formal requests to the union asking for some members to work during the strike under the "life-preserving services" provisions of the Employment Relations Act.
"We will be asking for a range of life-preserving services across the country. It will vary hospital by hospital," said Patterson, the chief executive of the Whanganui DHB.
When asked if there would be an appeal for the community to see GPs early and to keep hospital EDs for genuine emergencies, she said: "Not immediately. That may happen in some communities and not others."
She did not yet know how many patients would have elective surgery or outpatient appointments postponed as a result of the strike.
A 48-hour strike in 2008 affected more than 8000 such patients.
Senior doctors' union executive director Ian Powell said today it was unfortunate the DHBs' dispute with the Resident Doctors Association (RDA) had come to a strike. He hoped the parties could yet find a negotiated solution, but admitted: "The signs don't look good."
He noted the RDA was trying to deal with fatigue, while a survey of his own members had revealed concerns about senior-doctor burn-out. DHBs were "ignoring the calamity" of the work pressures experienced by doctors.
Patterson expressed frustration over the RDA survey, which the union says found that 1182 identified having made a mistake as a result of work fatigue and 275 had fallen asleep while driving home.
"The RDA survey was done anonymously. We haven't seen anything except high-level results from that," Patterson said.
"We have done our own survey of DHBs. We have got no examples anywhere in the country where there has been outside-of-work falling asleep at the wheel or patient safety mistakes that are attributable to fatigue that they have reported.
"We have plenty of provisions if people are tired or feel they are not fit to work ... we can seek help and put replacements in place."