A total of 36 surgeries and more than 100 appointments have been cancelled as junior doctors at MK Hospital begin strike action.
Amid a row over pay and working hours junior doctors are providing emergency cover only during the 24-hour walkout, which began at 8am this morning.
MK Hospital chief Joe Harrison says his staff are working hard to rearrange as soon as possible.
He said: “We apologise for any distress caused to patients.
“Patients will be contacted directly by the hospital to reschedule any cancelled appointments. If any patient is concerned, please contact the clinic number on your letter.”
More than 4,000 routine treatments have been postponed so far, not including the number of appointments which have had to be rescheduled.
Last week, hospital bosses warned that patients may experience longer waiting times than normal.
Professor Martin Wetherill, Medical Director at Milton Keynes University Hospital NHS Foundation Trust, said: “Let me assure the local public that our staff will continue to provide excellent care throughout the three periods of industrial action and ensure all of our patients remain safe.
“The hospital has robust and extensive plans in place for all the emergency patients who will be attending between 8am on January 12 to 8am on January 13.
“We have tried and tested these plans to minimise any disruption during this period and, most importantly, to keep our patients safe and thank visitors in advance for their patience during these periods.
“We are contacting those patients that are affected by the reduction in our elective services and for those whose services have been postponed; we will be in touch to rearrange appointments as soon as we can.”