The HSE is urging people not to go to A&E if it’s not an emergency.
The health agency has published its €30 million winter plan, which includes a major focus on overcrowding and supporting older people.
The plan will run from December to March - with extra measures at nine hospitals around the country from the 17th December to the 13th January.
75 acute beds will come on stream at these hospitals with 66 community beds also being made available for the elderly.
The HSE’s Vida Hamilton explained: "There are three aspects to our winter plan - admission avoidance, patient flow, and supported discharge.
"We know that 20% of our admissions during the winter time are due to chest infections - this is an opportunity for us to reduce that number."
Health Minister Simon Harris said the winter plan as a whole “represents a system wide response to this challenge across the health service".
He added: "It will be led at national and local level by integrated teams representing community and hospital services.”