The Southern Trust Board is being asked to approve contingency plans should A&E services at Daisy Hill Hospital be temporarily suspended.
Southern Health Trust board members are being briefed on Thursday about the latest moves to save the service.
Last week, the trust told staff overnight closure may be unavoidable due to staff shortages.
The trust says the emergency service is vulnerable at night due to a shortage of permanent senior medical staff.
In a statement, the trust said contingency plans will be outlined to ensure patients can continue to access safe, high-quality care in the unfortunate event that medical cover cannot be secure for more than one night.
The BBC understands that while there should be around 10 senior permanent doctors employed - at the moment the trust has just two permanent senior medics.
One of these is part-time and the remaining shifts are being filled by locums.
The trust says attempts to recruit have been unsuccessful, and it is now asking the Southern Trust Board to approve preparations in Craigavon Area Hospital to accommodate an additional flow of patients should the Daisy Hill service be suspended at night.
The move by the trust would suggest it is not if, but when the overnight service will close. Total closure would require public consultation.
Staffing the emergency department and meeting European safety regulations has been a challenge for several of Northern Ireland's health trusts, but particularly the Southern Health and Social Care Trust.
What has happened is partly down to the fact that the reform of healthcare services in Northern Ireland has yet to happen.
Under the Transforming Your Care health review and last year's Bengoa report, reform was suggested not as a choice but as a necessity.
Last year, more than 53,000 people attended Daisy Hill Hospital's emergency department.