The number of people in hospital with flu has been increasing rapidly, with 869 this morning compared to 530 people last Sunday, according to the HSE.
On Friday there were 742 people admitted which increased to 809 yesterday.
HSE CEO Bernard Gloster said the numbers to rise to around 900 in the coming week.
“We are taking several measures to prepare for the potential surge in hospitalisations and intensive care admissions due to the flu," he said.
"The intensive care capacity is currently managing, with 323 available beds and 300 people in ICU, though not all of them are flu cases, but the flu adds pressure to the wider system.
“Between 20th and 27th of December, 34,400 people attended emergency departments, an increase on 27,800 for the same week last year.
"8,500 patients were admitted compared to 7,800 for the same period last year yet we have fewer people on trolleys.
"Record discharges over the course of this seven day period is keeping the system to some degree stable.”
The HSE is continuing to urge people to stay at home and seek alternative treatments where possible.
It has recommended to instead visit pharmacies or local GP's for non-life threatening conditions.