Health chiefs confirmed 26 patients were tonight being treated in intensive care units for flu.
Official figures revealed 114 people have been hospitalised from influenza, including human swine flu, since the start of October.
Of those, 33, including two pregnant woman, were admitted to intensive care - where 26 remain.
Tony Holohan, chief medical officer, warned the figures would rise over the coming weeks and advised at-risk groups, including the elderly, ill and pregnant women, to be vaccinated.
But he stressed the virus was just a routine seasonal winter epidemic and not a pandemic which needed a crisis response.
“This is something we both expected and anticipated,” he added.
Dr Kevin Kelleher, head of health protection with the Health Service Executive (HSE), denied the rise in the influenza virus had impacted on A&E Departments where hundreds of patients had been left on hospital trolleys.
“Hopefully that’s because people have been heeding our message about what we have been saying about the flu, that it’s a self care issue and, in a sense, the first place they should be going is to their GP, preferably by phone,” said Dr Kelleher.
The Irish Association for Emergency Medicine (IAEM) also dismissed the HSE’s claim that increasing numbers of swine flu cases were to blame for the spike in waiting times.
Statistics showed the rate of flu infection increased significantly over recent weeks to 120 per 100,000 population, with an estimated 89% suffering from H1N1. Peak rates during last year’s pandemic, when 27 people died, was over 200 per 100,000 population.
Mr Kelleher also told people to protect themselves and others at-risk by catching coughs and sneezes in a tissue, disposing of it in a bin, and washing your hands and surrounding surfaces.
“This is a disease that is quite infectious so as soon as you are feeling unwell it is appropriate to isolate yourself in your bedroom,” he added.