Whanganui District Health Board is putting together a plan for when 17 of its resident doctors go on strike.
WDHB chief executive Julie Patterson said she had received confirmation from the New Zealand Resident Doctors Association that its members would strike from October 18 to October 20.
Mrs Patterson said the DHB would ensure "as many services as possible" were maintained during the industrial action.
"Because only 17 of our 38 [resident doctors] are members of the union, the disruption to services in Whanganui will be less than we were originally expecting."
She said that if any services do need to be postponed, patients affected will be directly contacted by the DHB.
Mrs Patterson said she respects the union members' right to strike, but she is concerned that the union is "undermining the public's confidence in health services".
"Disguising a pay claim as a health and safety issue, which leads to the community worrying about the safety of our services, is just irresponsible.
"The facts of the working conditions of these valuable staff members have been distorted by the union. Yes, the RMOs may work 12 days in a row but nationally this only occurs around once every six to eight weeks. Yes the RMOs may work a long day - 16 hours - but again nationally, not more than once a week, nor every week. Whanganui rosters are more frequent due to its smaller size."
Mrs Patterson said the DHB had had just one instance of medical staff reporting concerns about fatigue.