Tallaght University Hospital has said it is struggling with a very high number of emergency cases.
In a statement last night, the hospital asked those with minor injuries or illnesses to go to a GP first.
The hospital said: "ED patients are seen in order of priority which may result in patients with minor illnesses or injuries experiencing delays.
"We would like to thank the general public for their understanding and cooperation during this busy period."
Record trolley numbers were recorded yesterday by the Irish Nurses and Midwives Organisation (INMO).
714 people across the country were waiting for a hospital bed on trolleys and in wards yesterday morning - a new all time high.
Those figures included 40 in Tallaght and 32 in the Mater.
The pressure's led to the HSE cancelling all non-urgent surgeries.
The Health Minister also announced €5 million in extra spending to speed up the discharge of patients.