Three elderly people have died and five children are in intensive care after a major spread of flu in the past week.
The country is now in the grip of a major flu outbreak, which is posing a particular risk to the over 65s.
Eight flu deaths have so far been confirmed since the middle of January and the spread of the virus is continuing to increase.
Swine flu is one of the dominant strains circulating since the beginning of winter and has been been responsible for three of the deaths.
The national threshold for flu spread in Ireland is 21 cases per 100,000 but it is now at double that level, new figures reveal.
The seasonal flu jab protects against all the strains, including the swine flu, which pose a danger this winter and at-risk groups are still advised to get the vaccine.
The flu has so far claimed the life of one toddler, an older patient and six pensioners after nursing homes were hit by a number of outbreaks last week.
Complications from the virus led to 34 people being hospitalised with flu last week across the country, and 31 have had to be transferred to intensive care this winter, 18 of whom had swine flu, according to the disease watchdog, the Health Protection Surveillance Centre. Five children under the age of five required intensive-care treatment.
Swine flu first emerged in 2009 and caused worldwide panic because of the lack of a vaccine. However, disease experts pointed out yesterday it is now just like any other flu virus and there has been a vaccine available for some years. Many people are now resistant to it.
Cork University Hospital has already confirmed a number of cases of swine flu in patients in recent days and is imposing strict visitor restrictions, with just one named visitor allowed per patient a day. No children are allowed.
Other hospitals imposing similar restrictions are Beaumont Hospital in Dublin, Kerry General and Limerick maternity hospital.
The Cork hospital is confining the patients with flu to one ward in a bid to halt its spread.
Before a vaccine to protect against swine flu was manufactured there were a small number of cases that resulted in serious illness and death, but they were mostly in people with pre-existing health conditions, such as cancer.
However, during pregnancy, the immune system still functions and the risk of complications is very small.
The symptoms of flu usually develop over a matter of a few hours and include a high temperature, sore muscles, dry cough, headache and sore throat.
Anyone who gets flu should stay at home, rest, drink plenty of fluids and use over-the-counter remedies like paracetamol to ease symptoms.