The HSE has issued a public advisory as UHG is under serious pressure.
Over the weekend, there were more than 350 presentations at the Emergency Department.
According to the INMO, there are 68 patients waiting on trolleys today.
In a statement, the hospital also says it continues to manage multiple outbreaks of COVID-19 and Norovirus cases.
Some elective procedures are being cancelled, surge areas are in use, and patients attending for non-urgent treatment will experience long wait times.