HSE says there are delays for there for "patients who need non-urgent care."
A Kildare man has spent almost 17 hours in Naas General's Emergency Department, without seeing a doctor.
John Kenna, from Kilcullen, attended on Monday, and was coughing up blood.
He had returned to his home from an appointment at Blackrock Clinic when he became unwell.
The HSE says Naas General's Emergency Dept. is "very busy", partially as a result of the cyber attack on the executive's systems.
It says "There are delays for patients who need non-urgent care."
Mr. Kenna, speaking to Kildare Today, says he became weak from prolonged fasting while attending the ED.
Mr. Kenna joined Clem Ryan on Wednesday's edition of the programme.