It follows a decision by the Trust and at least nine patients have had planned orthopaedic surgery postponed as a result.
Sinn Féin MLA John O'Dowd has described the cancellations of much-needed operations as a result of pressures in the health service as 'extremely concerning'.
The MLA said: “Cancelling non-urgent surgeries will cause further distress to patients on already out-of-control waiting lists and have a knock-on effect on emergency departments.
“Years of Tory cuts to the health service have caused so much distress for patients. Frequently, I hear concerns from some of my constituents in Upper Bann currently on waiting lists - the stress caused can be terribly overwhelming.
“This is extremely concerning. People want investment in health and social care to transform the system, to pay workers a fair wage, and bring an end to services and health workers being overwhelmed.
“They also want leadership and local ministers to be back around the Executive table working on behalf of these patients and staff. Sinn Féin are ready to do that.
“The DUP should get back to work with the rest of us to help invest additional resources in the system, to reduce waiting lists and recruit more doctors and nurses.”
A spokesperson for the Southern Health and Social Care Trust said: “The Trust has had to take the difficult decision to postpone some elective orthopaedic surgery. At this time 9 patients have had their planned orthopaedic surgery postponed.
"The Trust has also had to increase the number of trauma surgery sessions to meet the demand. The Trust is reviewing the situation daily and is working hard to ensure all postponed patients are offered a new date.”
Pressures on the health service both locally and nationally have been exacerbated by Winter flu and a rise on Covid-19 cases, however a major issue for hospitals is a lack of social care in the community which is leading to bed blocking on wards and creating a ripple effect in the Emergency Departments and the Ambulance Service.