The Midland Regional Hospital at Mullingar has been taken off-call due to overcrowding at the hospitals Accident and Emergency department.
As a result ambulances are being re-directed to other hospitals in the region.
It is understood at least 22 people were waiting to be admitted on trolleys this morning with no further trolleys available.
According to the Irish Nurses Organisation (INO) the hospital has seen an 800 per cent increase in the number of patients waiting on trolleys in November 2009 compared to figures for November 2007.
They say this increase is attributable to the closure of 41 beds in the hospital.
Lorraine Monaghan of the INO called the overcrowding “unsafe and unmanageable”.
“This situation will inevitably worsen as we enter into the depths of winter unless management take immediate action and reopen the recently closed beds in the Hospital,” she added.
However, the Health Service Executive disputes the claim and says the hospital has seen a reduction of 21 beds.
In a statement released this evening the Executive said following the transfer of patients to the upgraded ward areas in the hospital in November the new bed compliment stands at 199 compared to 220 previously.
It said the “increased provision of day care beds which will ensure that the Midland Regional Hospital Mullingar treats more patients in 2010 than 2009.”
A HSE spokeswoman said the hospital remains open to the general public.