Mason said contingency planning for the proposed strike had been ongoing for the last three months.
Those plans were now being implemented and some services, such as elective (planned) surgery, would be rescheduled to reduce patient numbers.
Patients affected by the strikes will be contacted and given details of what the changes mean for them.
For more information on appointments, patients can also call the BOPDHB freephone Patient Information Centre number 0800 333 477 which is available from 7.30am to 6pm Monday to Friday.
If the strike goes ahead, people should not delay seeking medical treatment, and should still go to hospital if the matter is urgent. Dial 111 for emergencies or an ambulance.
For all other matters people should do what they normally do and visit their GP or a local pharmacy.
Free medical advice is also available 24/7 through Healthline (phone 0800 Healthline - 0800 611 116).
For more information, and a list of which services will remain open, which will be reduced and which will be closed, go to www.bopdhb.govt.nz