Belfast Trust has announced it is cancelling 105 planned surgeries over the next two weeks as it expands capacity to deal with a surge in coronavirus patients.
The surgeries had been due to go ahead at Belfast City Hospital and Musgrave Park Hospital.
However, the number of patients in Belfast Trust hospitals who are Covid positive is continuing to rise, the Trust said.
Meanwhile, an Executive announcement on the potential for a circuit-breaker was yet to be made after MLAs left Stormont on Tuesday evening.
The Assembly is now expected to sit at 10.30am to discuss what is agreed by ministers this evening.
It comes after Mr Swann released a health paper that warned of rising cases unless schools and businesses in the hospitality sector were not shut down.
The Trust took the decision to cancel elective surgery this week and relocate and expand its Covid ICU from the Mater to the Belfast City Hospital Tower Block.
The facility is not yet being stood up on a region-wide basis, but will be accepting Covid-19 patients being treated within the Belfast Trust area.
Any move to reopen Belfast's Nightingale facility to patients across Northern Ireland would need to be initiated by health minister Robin Swann.
A Belfast Trust spokesperson said: "Today we need to expand our intensive care beds to Belfast City Hospital (BCH) to cope with the increase of patients ventilated at the Mater Hospital. We are able to care for up to 11 ventilated patients at the Mater Hospital and currently we are caring for 10.
"Regrettably, the data tells us that we are likely to have more Covid positive ICU patients in the coming days. We therefore need to be in a position to continue to care for Covid positive ICU patients, and receive the next wave of intensive care patients into BCH.
"To do this we need to have staff available and ready in BCH. A 10-bedded intensive care ward requires up 80 clinical staff, in addition to support services, to safely care for patients. This is a huge draw on our staffing resource who are grappling with pressures in their own areas of work. While we have a plan as to how to free colleagues to work in BCH, regrettably it means we have to postpone elective procedures in some areas this week."
These measures are intended to give the Trust the opportunity to upskill staff to support the anticipated rise in patients being admitted with Covid-19 both to hospital, and to an expanded ICU in BCH.
The Mater Hospital will continue to treat Covid-19 patients who do not require ICU level care in its role as Covid-19 Belfast Hospital.
It comes as a further seven people in Northern Ireland have died after testing positive for Covid-19 and 863 new cases of the virus have been reported.
This brings the death toll to 598 and the total number of confirmed cases since the outbreak to 21,898. Some 6,286 people have tested positive in the last seven days alone.
Of the seven fatalities, four happened within the current reporting period, from 10am on Monday, October 12 to 10am on Tuesday, October 13, while three occurred previously.
There are currently 150 Covid patients in hospitals across Northern Ireland, with 23 patients in intensive care and 15 requiring ventilation.
A total of 53 care homes are dealing with outbreaks of the virus.
Here's how Tuesday unfolded:
The epicentre of the coronavirus outbreak in Northern Ireland has been Belfast where there have been 9,567 confirmed cases and 191 deaths recorded by the Department of Health to date. But Mid Ulster and the North West are current hotspots.