Beaumont Hospital is owed €307,000 by people who were treated in its emergency department.
The hospital recorded 39,195 attendances at its emergency department between January and September last year, of which 36,288 were new patients and 2,907 returns.
A statutory charge of €100 applies for patients if they are not referred by a GP to the emergency department.
However, certain groups are exempt from the charge, including medical card holders and people admitted to hospital as an in-patient as a result of attending the emergency department.
Beaumont said the number of patients liable to pay the charge in the first nine months of last year was 5,766.
"All these patients have been charged the €100 statutory charge," the hospital said in response to a question under the Freedom of Information Act
"A further charge will apply for attendances in relation to road traffic accidents as the full economic cost is applied in these cases, at a rate of €446.82 for the first visit and €223.30 for return visits.
"Non-residents will also be charged the full economic cost of €446.82 for their attendance."
The hospital said that 575 patients paid in the emergency department at the time of their attendance, and 5,192 were invoiced subsequent to their emergency department visit.
The total amount that was outstanding by the middle of last month was €307,580, a hospital spokesman revealed.
"This will include the statutory charge owing for patients treated due to a road traffic accident injury, but excludes amounts outstanding in relation to the further road traffic accident charge," the spokesman said.
If patients do not or cannot pay on the occasion of their attendance, an invoice is forwarded to their address after their visit.
These are due for payment within 30 days of the invoice date.
In the event of non-payment of the account, the hospital uses the services of an external debt collection agency to recover the outstanding debt.
Recovery of road traffic accident accounts is managed separately.