The Health Service Executive has urged people to get the flu vaccination after it confirmed a number of deaths from the so-called 'Aussie flu' strain.
In a statement, the executive said the number of reported cases of flu had increased in the week before Christmas and that flu "is now actively circulating in Ireland".
It is urging people, particularly those in high-risk groups, to make sure they are vaccinated.
These include people aged 65 and over; anyone with a chronic illness; all pregnant women as well as people in care homes or long stay facilities.
Director of the HSE's Health Protection Surveillance Centre Dr Kevin Kelleher said the executive has been informed of a "small number of deaths directly related to influenza (less than ten)" in the last two weeks.
He said it is not too late for people at risk to get the vaccine and prevention is better than cure.
The HSE said that Australian flu season has been dominated by influenza A (H3N2) co-circulating with influenza B, but that the H3N2 is similar to the strain which dominated last year’s flu season in Ireland.
This strain of flu was included in the vaccine, which has been available in Ireland since September, for this flu season.