The Irish Nurses and Midwives Organisation says it is imperative that Beaumont Hospital go off call immediately for an extended period due to severe overcrowding in the Emergency Department.
The organisation says there are 92 patients in the department, 38 of whom are waiting on trolleys and chairs for a hospital bed.
The INMO does not expect many beds to become available soon which may mean the situation deteriorating further.
INMO Industrial Relations Officer, Lorraine Monaghan, said: "This situation is unsafe yet nothing is being done to address it. Patients are at serious risk and staff are at breaking point.
Ms Monaghan said the INMO wrote to HIQA looking for them to inspect the Emergency Department and see the overcrowding problem there.
She said: "However, HIQA advised that, while they recognise the seriousness of risks, they do not have resources to carry out any such inspection.
"This is an appalling situation where the national health watchdog cannot carry out its basic function."