The average wait time for admission to emergency departments for patients over 75 years old was almost 14 hours last month, according to the HSE.
The HSE provided the data after a parliamentary question from Sinn Féin's health spokesperson David Cullinane.
Patient Experience Time is the length of time a patient spends in an Emergency Department from registration until discharge to a hospital bed or discharge home.
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A patient's wait time starts as soon as they walk through the doors of an emergency department and does not end until the patient is either discharged home or admitted to hospital.
This means it does not describe the time a patient is waiting to be seen but the total time they spend in ED.
The data showed that the average waiting time was nearly twice as long as wait times in two Cork hospitals.
The average wait was 28.8 hours at Cork University Hospital, and at the Mercy Hospital in Cork, it was 26.8 hours.
The average wait times were shown to be higher for those over-75 when compared to those aged under 75, for all hospitals with the exception of four, with over-75s waiting on average up to 7 to 9 hours longer.
The head of the HSE said the health service had seen one of its worst quarters, which had contributed to waiting times in emergency departments.
HSE Chief Executive Paul Reid told the Oireachtas Public Accounts Committee that a "major impact on our hospital services" from Covid is still being experienced in hospitals across the country.
He said the first quarter of the year was "one of the worst quarters that we've seen throughout Covid" and added that we are now seeing "higher presentation" for the over-75s, who have "more complex needs".
Mr Reid said the HSE would "continuously commit to the Sláintecare strategy" to relieve the pressure.
The current strategy includes 30 multi-disciplinary teams providing care for older people in the community.
Secretary General of the Department of Health Robert Watt also reiterated that Sláintecare would be vital in providing a solution for the delays.
The HSE said many factors had caused longer wait times, such as higher volumes of patients presenting and the requirement to prioritise, treat and care for the sickest and older group of patients and those with life-threatening illnesses.
It said that patients with less severe illnesses and conditions might need to wait longer for their treatment.
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