More than 90,000 bed days have been lost in the hospital system so far this year because of delayed discharges, according to Health Service Executive figures.
The information was supplied to Fianna Fáil's health spokesman Billy Kelleher.
Patients are classified as "delayed discharges" when they no longer need to be cared for in an acute hospital setting but have no access to appropriate step-down care.
Mr Kelleher said the fact that hundreds of patients are lying on trolleys in emergency departments or in wards is directly related to the number of bed days lost in the system.
He added that the loss of over 90,000 bed days when there are over 86,000 people waiting for treatment is not only unacceptable but unjustifiable.
He said it is "further evidence that the level of support being provided to mainly older patients is simply not good enough".
The HSE's National Director of Acute Hospitals has said the average number of delayed discharges this year is 536 per day, which is an improvement on the previous three years.
Speaking on RTÉ's Morning Ireland, Liam Woods said there is a clear need to invest in primary and community services in order to facilitate faster discharges, which he said has been identified in the future healthcare plan.
It was important to remember, he said, that these patients still need medical care and cannot be discharged until appropriate help has been lined up.
Delayed discharges can result in surgery cancellations, he said, but added that capacity and surgical delivery in hospitals is improving.