The Health Service Executive has reported a sharp increase in the number of cases of influenza-like illnesses, estimating the flu was likely to circulate over the next six to eight weeks.
Speaking on RTÉ's Morning Ireland, HSE Health Protection Surveillance Centre director Dr Darina O'Flanagan said four people have died as a result of flu this winter while 89 people have been admitted to hospital.
Dr O'Flanagan said those figures are expected to rise over the coming weeks.
She stressed that it was not too late for people to get the flu vaccination, which she said would cut down the risks of getting the illness.
She urged people from high risk groups to get vaccinated saying the flu is "actively circulating in the community."
High risk groups include those aged 65 and over, people with a long-term medical condition and pregnant women.