People over the age of 75 were waiting more than 17 hours at University Hospital Kerry's emergency department in June.
Preliminary data shows that people aged 75+ waited that length of time from registration to admission.
Those aged under 75 were waiting more than ten hours on average.
Advertisement
The figures were provided by the HSE to Sinn Fein Spokesperson for Health David Cullinane.
The HSE says the data is preliminary and is subject to change.