Five people were admitted to hospital with confirmed flu last week as the virus tightened its grip.
Flu levels are still low but rising, according to latest reports.
The main strain circulating this year is swine flu, and the seasonal vaccine provides good protection against it.
However, it can strike pregnant women and the young. Patients who contract the virus have a higher risk of ending up in intensive care units.
No confirmed flu cases were admitted to critical care units last week, the report from the Health Protection Surveillance Centre said.
It comes as hospitals step up measures to transfer more than 540 patients known as bed blockers - people who no longer need acute care.
The HSE has an additional 300 home care packages to give to patients who still need support after leaving hospital.
Others will go to transitional care beds. The exodus is aimed at freeing up beds before the surge in attendances after Christmas and early in the new year. Figures provided to the most recent meeting of the emergency department task force showed that St James's Hospital had 72 patients who no longer needed acute care.
There were 62 in Beaumont Hospital, 51 in Tallaght Hospital and 49 in the Mater. All these patients are occupying beds but could not leave until proper supports were available.
There were 37 of these patients in St Vincent's Hospital and 28 in Connolly Hospital.
"My department is working with the HSE to ensure the most effective response to the winter challenges to unscheduled care provision," Health Minister Simon Harris said.
"Within this context, the HSE requested singular integrated winter plans from hospital groups and community health organisations in June 2018. Subsequently, in September and October 2018, I met with hospital groups and community healthcare organisations to discuss their plans for winter preparedness."
The HSE Winter Plan 2018/19 provides for a four-week enhanced focus period from December 17 to January 13, targeting nine key sites of concern. Naas General Hospital has been identified as one of these, based on performance in previous winters.
"As part of Budget 2019, an additional €10m in funding is being provided in 2018 for social care measures to enable older people to leave hospital and return to a more appropriate care setting, including their own home, as quickly as possible with the supports they need.
"My department has sanctioned the release of €5m of this additional funding to enable the deployment of social and primary care measures to support this transition.
"Increasing bed capacity is a Government priority. Over the past 12 months an additional 240 beds have been opened, including 11 additional beds in Naas General Hospital and a further 78 additional beds are due to come on stream nationally in 2019."
Talks on investment in more beds in 2019 are under way.