Hospitals in Greater Manchester are treating "more Covid patients than at the peak of the first wave", resulting in non-urgent care being suspended.
Non-urgent hospital surgery and appointments will not go ahead as planned as coronavirus admissions have increased by 64 patients in a week.
Urgent and emergency care, such as cancer treatment, will continue.
Hospital chiefs said non-urgent work was "pausing" to ensure critical care facilities could be expanded.
Those affected by the delay will be contacted by hospitals, a spokeswoman for Greater Manchester Health and Social Care Partnership said.
Hospital admissions of coronavirus patients in the region have risen to 132 in the week ending 3 November, compared to 68 during the week ending 27 October.
Before a nationwide lockdown came into force in England on Thursday, Greater Manchester had been in the highest level of the three-tier system of restrictions.