The flu outbreak has claimed a total of 15 lives this winter. Three more deaths have been reported in the last week.
The Health Protection Surveillance Centre (HPSC) said the swine flu virus accounted for just over a third of all flu cases. Almost two thirds of overall flu cases were Influenza B.
However, 11 of those who died, were suffering from H1N1 swine flu and 14 of the victims had underlying health conditions.
A child aged under four years was among those to die. Ten victims were in the 15 to 64 age group, while the four other patients were aged 65 and older.
The HSE said the flu season had peaked, with 4,194 new cases reported during the last seven days. Swine flu accounted for 37% of cases.
Thirty-eight people are still being treated for the flu in hospital intensive care units this evening.
The HPSC has warned that while the number of new cases is in decline, levels among schoolchildren aged from five to 14 continue to rise.
Two more people with swine flu have died in the North, bringing the total number of deaths there during this flu season to 25.