People in the Northern Sound region have been advised that "significant delays" are to be expected at Cavan General Hospital's Emergency Department.
A spokesperson says the hospital is "currently experiencing significantly high levels of activity, with prolonged waiting times".
There are also a "high number of patient presentations to the Emergency Department" and "limited bed capacity".
Patients are being asked to "explore" alternatives to an Emergency Department referral and Cavan Hospital has thanked the public for its co-operation.