Dr Tom Reynolds, resident medical officer at Rotorua Hospital and New Zealand Resident Doctors Association delegate, said the main stumbling block was safer rostering practices.
"Everyone knows we get tired when we work these patterns, we have to juggle a lot of balls in our day-to-day work and if we are tired we do this much less effectively.
"It's really important to ensure the safety of patients by avoiding having tired doctors."
Dr Reynolds said it was not a decision that had been taken lightly and the Lakes DHB had already made some changes to its rosters, but had only gone part way to a final resolution.
"We wouldn't do this if we didn't have to. There's still time to avert the strike."
Lakes DHB communications officer Sue Wilkie said contingency planning meetings had begun in preparation for action across both hospitals - Rotorua and Taupo.
"Lakes DHB has a detailed contingency plan to refer to, refined in times of previous threats of strike action.
"Elective surgery cases will need to be postponed during the strike.
"Any decisions made about impacts on services will be taken to allow clinical staff to focus on those in most need."
Miss Wilkie said people should keep up to date with their prescriptions, and if they can, make their GP or Lakes PrimeCare their first port of call during the strike.
DHB national spokeswoman, Julie Patterson, said their offer would lead to New Zealand resident doctors, also called resident medical officers "having some of the best hours of work in the world".
"We have agreed to split night shifts that the union reports 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.
"Despite the DHBs' offer, the union has maintained its position of expecting DHBs to pay the resident medical officers for the days off that will result from the roster changes."
Association national secretary Deborah Powell said there was now no alternative to strike action and said DHBs had misrepresented their position.
Dr Harry Pert of Ranolf Medical Centre said their practice would cope and he supported the strike action.
"It's a very complex and demanding job these days and their hours are unrealistic.
"It's not something they would be doing lightly and are in a desperate situation and have been driven to desperate measures," Dr Pert said.
Lakes PrimeCare declined to comment.