The number of people in hospitals with flu has increased rapidly, with a total of 869 cases admitted as of this morning, the HSE has said.
On Friday, 742 people were admitted to hospital with flu, with a further 67 admitted yesterday.
There were 530 people with flu in hospitals last Sunday.
Health Service Executive CEO Bernard Gloster said the numbers are expected to increase, but cases are still estimated to peak at around 900 in the coming week.
Speaking on RTE's This Week, he said that between 20 and 27 December, 34,400 people attended emergency departments and that 8,500 were admitted compared to 7,800 for the same period last year.
Mr Gloster said the issue now was not the peak of the flu, but rather how long the tail of the flu will last, which can impact right through January.
"We are very much in charge of it ... but we need the public's assistance both in controlling the circulation of flu and also what they do when they experience flu like symptoms," he said.
Mr Gloster said if people experience chest pain or breathing difficulties, they should go to an ED if "no other clinician is available to you", but otherwise to seek advice from their GP or local pharmacist.
Mr Gloster said that the HSE is managing staffing issues and sickness, but is expecting an increase in demand this week, and so people can expect delays.
"Overall the patient flow system is moving much better than last year.. We are continuing to focus on every lever we can pull to keep the patient flow system moving and keep everybody safe," he added.
He urged anyone with flu-like symptoms to avoid visiting hospital and for everyone to cooperate with hospital staff when it comes to visiting.
