Following mediation yesterday, the DHBs tabled an offer which gave a "commitment to implement" the four night maximum, and a "commitment to addressing" the 12 consecutive days issue.
NZRDA national secretary Deborah Powell said the strike followed 10 months of bargaining. She said Northland DHB had been among the first to introduce improvements to its rosters, but had then "stalled".
"We have a situation in Northland where its OK for some doctors but not others," she said.
In Northland, rosters for medical registrars and paediatric resident doctors were still not in line with the NZRDA's requests, Ms Powell said.
"For Northland to finish this process it would only take another 1.5 doctors," she said.
Resident doctors range from doctors in their first year out of medical school to registrars training in a specialist field. There are 3500 resident doctors nationwide, 90 per cent of whom were represented by the association.
The strike would affect staff at Kaitaia, Whangarei, Bay of Islands and Dargaville hospitals, as well as some working in community-based health services.
Spokeswoman for the 20 DHBs, Julie Patterson, said she was disappointed by the result of yesterday's negotiations. Had the association accepted, its doctors would have "some of the best hours of work in the world", she said.
"We have agreed to split night shifts that the union report cause fatigue. We have given an assurance that the maximum number of days worked in a row will be reduced to 10 days and we have provided a framework to fast track the changes required," Ms Patterson said.
"The union has maintained its position of expecting DHBs to pay the [resident doctors] for the days off that will result from the roster changes."
The DHBs would now turn their attention to further planning for the strike.
"The DHBs' planning for any industrial action is well advanced," Ms Patterson said. "The public will be advised individually if there is any disruption to planned services."