Recent statistics issued by the INMO indicated that thousands of patients across the country were left without hospital beds in 2019.
"These patients are often being treated on trolleys in corridors, but they may also be on chairs, in waiting rooms, or simply wherever there's space", notes the INMO.
In a statement, the QEH said: "To help prevent the risk of infection spreading and ensure the safety of our patients and staff, we are encouraging people not to visit hospital, wherever possible, especially if you have been unwell yourself".
They show 15 patients on trolleys and 17 on wards, giving a total of 32 people waiting on a bed.
The previous worst-ever day was March 12,2018 during the "Beast from the East", when 714 patients went without beds, said the Irish Nurses and Midwives Organisation (INMO).More news: Samsung reveals groundbreaking curved Odyssey gaming monitors
In response the Health Minister Simon Harris says 50 beds will open today and 199 will open by the end of the month.
"We also need to immediately scrap the HSE's counterproductive recruitment pause - which is leaving these services understaffed and thus overcrowded", she said.
"We are asking people to think about all their care and treatment options and keep ED services for the patients who need them most. You can visit www.hse.ie/winter or www.undertheweather.ie for useful advice and self-care tips for treating mild viral illnesses".
Meanwhile, all elective surgery is to be cancelled at Cork's two main hospitals in a bid to tackle overcrowding, which reached a record high yesterday.
According to the INMO, 433 patients nationwide are waiting in the emergency department, while 187 are in wards elsewhere in the hospital.More news: Indonesian student jailed as Britain's worst rapist
The INMO warned that CUH and Mercy University Hospital were operating "beyond their limits".
Around one third of the hospital's wards now contain patients with flu or other respiratory viruses.
"Hospital management is appealing to both adults and children who are experiencing any signs or symptoms of influenza to contact their local health provider (GP/ Southdoc) in the first instance prior to attending the hospital".
She said the major incident protocol should see elective surgeries cancelled, non-emergency admissions stopped and extra bed capacity sourced from wherever it can be found.More news: Sen. Graham Urges Senate Rules Change to Speed President Trump's Impeachment Trial