The HSE is urging the public to utilise "all care options before attending Emergency Departments (EDs)" over the June bank holiday weekend.
Amid ongoing record overcrowding at hospitals around the country, the HSE said EDs must be protected for patients who require urgent and emergency care.
"This year, hospitals have reported record numbers of patients presenting at Emergency Departments for care and treatment, including a sharp increase in the number of patients who are seen and treated in the ED and then discharged without requiring admission to hospital.
"Many of these patients could have been treated at other healthcare services such as Injury Units, GP and GP Out of Hours services and pharmacies," a statement from the HSE said.
Patients who attend an ED for "routine and non-urgent treatment" were warned they will experience "very long waiting times over the coming weekend and into early next week" as patients requiring urgent and emergency treatment will be seen first.
However, the HSE added that, as always, if someone is seriously ill or needs urgent emergency care, do not delay in attending an ED or dialling 999/112 for help.
