"Every hospital across the country is experiencing a significant surge in terms of activity," HSE Regional Executive Officer for the Mid West Sandra Broderick has said.
"There has been an 18% increase during the festive period and that represents 9,000 more people who have attended emergency departments compared to 2023 between 20 December and 2 January.
"So really, really high attendances."
Speaking on RTÉ's News at One, Ms Broderick said that "a lot" of people required treatment in hospital for the flu.
"Coupled on top of that, in my own region at UHL, we have this weather alert that's leading to a lot of trauma and orthopaedic admissions right now," she added.
She said that hospitals are "expecting ongoing pressures for the rest of the month" with the flu and bad weather.
"We’re definitely likely to see disruption, particularly in areas affected by the weather and we’re expecting to see even more attendances given that people will have slips, trips and falls."
Ms Broderick apologised to people who experienced care on trolleys at UHL.
"Despite the fact that there were 60 odd people on trolleys at UHL this morning, the staff there are working extremely hard to progress all of those patients through our system," she said.
She encouraged people to use pharmacy, GP and GP out of hours services if possible, but said that if people have critical or serious illness they should attend the emergency department.
"They will be seen and they will be treated".
Kerry University Hospital has postponed all outpatients until Thursday, she said, and people should check the HSE website for service disruptions.
Ms Broderick said that people should contact their local service if they have questions about their appointments and that they should not travel unless safe to do so.
Sligo University Hospital remains under significant pressure
Sligo University Hospital remains under significant pressure with very high flu rates and high numbers attending the Emergency Department.
In a statement, the Saolta hospital group said the hospital is currently treating 29 patients with respiratory illnesses including flu and RSV.
In addition, there are 31 patients on trolleys awaiting admission to in-patient beds.
The hospital is postponing some elective procedures due to the pressures and the lack of bed capacity.
Urgent, time sensitive cases are being prioritised and patients are being contacted directly if their procedure is being postponed.
There is a flu outbreak in four wards and the hospital is restricting visiting to the affected wards.
Saolta is appealing to the public not to visit the hospital if they are unwell or have symptoms given the severe impact of the outbreaks.
Visitors are also advised that they must use the alcohol hand gels supplied as they enter and leave the hospital.
There will also be a requirement for all visitors to wear face masks.
Saolta expects the pressure at Sligo University Hospital will continue over the coming days.
It is urging the public, where appropriate to use alternative healthcare services for treatment such as GP, GP Out of Hours, the Roscommon Injury Unit and pharmacies.
INMO urges emergency plan as 761 wait for hospital bed
Meanwhile, the INMO has called for an emergency national plan deal with hospital overcrowding, with 761 admitted patients waiting for a hospital bed this morning.
The hospital worst affected is University Hospital Limerick, with 122 people waiting for a bed, while there are 53 waiting at Cork University Hospital and 51 and University Hospital Galway.
Of the 761 waiting, 528 are in emergency departments with the rest waiting on wards or elsewhere in the hospital.
Irish Nurses and Midwives Organisation General Secretary Phil Ní Sheaghdha said that nurses, midwives and other healthcare professionals are working in unenviable circumstances in hospitals and community settings.
In a statement she said: "It is inconceivable that we are once again talking about how high trolley figures are on the first Monday in January.
"This level of overcrowding when dealing with the level of flu and RSV that we have seen over the festive season was entirely predictable but there has been no plan in place by the HSE and individual health regions to stem the worst of it."
Ms Ní Sheaghdha said that an emergency national plan is needed to deal with the escalating overcrowding problem.
"The number of patients on trolleys today exceed the inpatient capacity of each large hospital across the country. For example, the number of patients on trolleys exceed the number of inpatient beds in University Hospital Waterford and Letterkenny University Hospital combined. The continued delay of developing three elective-only hospitals, as per the Sláintecare plan is adding to the problem."
