15 acute cases were reported in the final two weeks of 2016
Seven people have died from the flu so far this season.
The Health Protection Surveillance Centre (HPSC) say all the deaths were in people aged 60 years and older.
Five were associated with influenza A(H3), one with influenza A, and one with influenza B.
A new report also found 15 acute respiratory infection (ARI) and influenza outbreaks were reported in the final two weeks of last year.
14 were reported as influenza outbreaks and one ARI outbreak with no pathogens identified.
Up to the week ending January 1st, 36 ARI and influenza outbreaks were reported - 19 of which were associated with influenza A, two were associated with RSV, one with parainfluenza virus, one with human metapneumovirus and 13 with no pathogens identified.
The majority of ARI and influenza outbreaks reported to date this season were in residential care facilities or community hospitals.
The HPSC say these are mainly affecting those aged 65 years and older.
While there have been four confirmed influenza A outbreaks in acute hospitals up to January 1st.
The HPSC says "confirmed influenza hospitalisations and influenza outbreaks are currently at high levels and are continuing to increase, with those aged 65 years and older most affected.
"Respiratory admissions reported from a sentinel hospital network were at very high levels.
"It is recommended that antivirals be considered for the treatment or prevention of influenza in high risk groups."
It says influenza-like illness (ILI) rates have risen to 51 per 100,000 population and are above baseline threshold levels.