Rates of swine flu infection have soared over the holidays with 34 people requiring hospital treatment and five of those needing intensive care.
The latest figures from the Health Protection Surveillance Centre (HPSC) show there were 91 cases of the swine flu virus last week, more than double the number in the previous week.
Out of a 120 confirmed influenza cases notified to the HPSC on December 30, 106 were swine flu.
Influenza A (H1N1 2009), swine flu, is the predominant influenza virus circulating in Ireland at present. According to the HSE, this flu virus mainly affects younger people and those with existing medical condition.. Women who are pregnant or have been in the last six to eight weeks are also particularly at risk.
Eighteen of the reported swine flu cases related to women who had recently given birth or who are currently pregnant and seven of these women needed hospital care as a direct result of the swine flu infection.
As the number of swine flu cases continues to rise some hospitals have introduced visitor restrictions to protect patients.
The HSE is reporting a major rise in people attending GPs and GP out-of-hours services with flu-like illnesses.
The consultation rate has more than doubled from 24.7 per 100,000 people at the end of November to 62.7 per 100,000 last week.
In a statement the HPSC said influenza-like illness rates are above baseline levels, with highest rates reported in children.
During the last flu season, 24 people with H1N1 died and the swine flu virus accounted for 98 per cent of all flu cases seen in Ireland.
The HSE has urged anyone who has not already received the seasonal flu vaccine, which protects against the H1N1 strain, to get it -- particularly pregnant or recently pregnant women, those with long-term medical conditions, people aged over 65, carers, and healthcare workers.
The HSE said that this year many people will be immune to the swine flu virus, either because they had the virus last year or because they received the vaccine.