Daisy Hill Hospital's emergency department will remain open 24-hours for as long as it is safe to do so, a health trust director has said.
Dr Richard Wright said the Southern Health Trust only had a third of the emergency consultant cover required.
He said even an enhanced salary had failed to attract senior staff to the County Down hospital's A&E.
The trust has warned that overnight closures of the department may be unavoidable due to staff shortages.
Earlier this month, the trust confirmed it was making preparations to expand emergency capacity at Craigavon Area Hospital in County Armagh, in case Daisy Hill's services have to be suspended at night.
People living in parts of the Mournes, south Down and south Armagh say the increased travel time to Craigavon would put lives at risk and more than 800 people attended a protest meeting on Monday.
Dr Wright told BBC Radio Ulster's Talkback programme that no-one from the trust was available to attend because of the short notice.
He also spoke about recruitment problems at the Newry hospital and how the trust had "gone around the world" to try to find the specialists.
"We've been out 10 times over the last two years, we have had very few applicants and we have been able to appoint only one consultant during that time," he said.
"We have also secured special permission [from the Department of Health] to advertise an enhanced package to make it more attractive than any other job financially in Northern Ireland and we have had no applicants for that post."
'Writing on the wall'
But he said recruitment was an issue for emergency departments around Northern Ireland and further afield.
"We have, within the Southern Trust, 10 consultant emergency department doctors, we probably need about 30 to properly staff both our departments and to cover also the smaller department in south Tyrone."
He also addressed concerns that the doctors would prefer to work in Craigavon than Daisy Hill.
"We have a third of the total consultants we need, if we forcibly rotate any more of them to Daisy Hill we would destabilise the situation in Craigavon and we would end up with two departments that were destabilised.
"The issue is not a lack of willingness to assist because they have been doing that. The issue is there are not enough consultants within the Southern Trust to cover two departments."
Seana Grant, who is part of the campaign to keep the emergency department at Daisy Hill, claimed some services at the hospital were being reduced.
"Consultants are being asked to stand over an emergency department that doesn't have the capabilities to deal with what they are being asked to deal with and as such, they are not prepared to work there any more," she said.
"They see the writing is on the wall and they are not prepared to take a long-term post in a hospital that they can see is being continually downgraded."