An inspection of St Bricin's military hospital in Dublin, which has up to 100 idle beds, has found it would not be suitable for public patients without significant investment.
Earlier this week, after Minister for Defence Willie O'Dea said he would make it available to the health service, it was hoped it might be used to ease pressure on other Dublin hospitals, particularly their A&E units.
A team from the Health Service Executive (HSE), as well as representatives of the nearby Mater Hospital, inspected St Bricin's on Monday.
A spokesman for Minister for Health Mary Harney said the team's assessment was awaited.
However, it is understood from informed sources that St Bricin's would not be suitable for use as a public hospital, or even as a stepdown facility for elderly patients, without significant resources being pumped into it.
The Mater Hospital said it was interested in accessing any idle beds which might be made available to it.
It is awaiting approval for a 25-bed transit ward for patients moving from A&E to wards, having submitted plans for it to the HSE in December.
It is understood also to be in talks about taking over a nursing home in north Dublin as a stepdown facility for its patients.
Meanwhile, nurses and members of the public took to the streets again yesterday to protest about continuing overcrowding in A&E units. Lunchtime protests were held outside St Vincent's Hospital, Dublin, and Limerick Regional Hospital.
As the protests got under way there were again 283 patients on trolleys in A&Es across the State, according to the Irish Nurses' Organisation, which complained that nurses in a number of hospitals were being told taking part in the protests or giving interviews to the media was not in their best interests.
They were being intimidated, the INO claimed. It said intimidation had been encountered at Tallaght, Beaumont and Connolly Hospitals. These hospitals denied intimidation, as did the HSE.
Ms Harney said this week she wanted to see all vacant beds used in the interests of patients. However, a shortage of nurses is hampering this. Some 25 beds have been closed at Leopardstown Park Hospital in south Dublin since Christmas due to nursing shortages, its chief executive, Pat Smyth, confirmed yesterday.
However, he said, hospital representatives had travelled to India last month in search of nurses and had recruited 10 who should be ready to work in the hospital by June, when he expected the beds to be reopened.
Leopardstown Park is a former British army hospital which has been run as a voluntary hospital for older people since 1979. It has 171 long-stay beds, and at least a third of its nursing staff are from the Philippines.
Meanwhile the report of inspections of several A&E units by the Health and Safety Authority will be published today. Violence against staff in the units was found to be a significant issue.