The Belfast Trust has cancelled some elective surgeries this week amid a rising number of coronavirus patients in hospitals.
In a statement, the trust said the decision comes as it moves to relocate and expand its Covid-19 intensive care unit from the Mater Hospital to the Belfast City Hospital tower block.
“This decision was extremely difficult and one that we did not want to have to make," said Medical Director Chris Hagan.
"We have, however, seen a significant rise in admissions related to Covid-19 in recent days and feel it is now necessary to move to this stage in our surge plan to ensure we can continue to deliver safe levels of care."
He added: “To patients who have had procedures cancelled this week I apologise that we are unable to provide the treatment you were expecting and it was not a decision we took lightly.
"We will do everything in our power to reschedule cancelled surgery over the coming weeks."
It comes as a further seven coronavirus-related deaths were confirmed in Northern Ireland, bringing the Health Department’s total figure for Covid-19 deaths to 598.
The department said four of the deaths occurred within the most recent 24-hour reporting period, and three happened outside of it.
Meanwhile a further 863 people tested positive for Covid-19, bringing the seven-day total for positive tests to 6,286.
Derry City and Strabane Council area remains the worst hit area, with a case incidence rate of 970 per 100,000 people over the last seven days.
A total of 1,461 people have tested positive in Derry City and Strabane region over the seven-day period.
The Health Department also reported that there are currently 150 patients in hospitals with coronavirus, including 23 in intensive care.
The Executive is meeting on Tuesday to discuss the next steps in dealing with the spread of coronavirus.