Dr Tony Holohan, Chief Medical Officer of the Department, said laboratory test results had confirmed a second case of Influenza Type A (H1N1).
The patient, an adult woman living in the east of the country, recently arrived from New York and has been informed of the result.
She remains at home where she is receiving appropriate treatment and is clinically well.
Her contacts are being identified in accordance with public health guidelines.
Dr Holohan said 'the presentation of this case does not come as a surprise. As has been said previously, we have expected further cases and indeed, still do.'
He said both the Department of Health & Children and the Health Service Executive had planned for this eventuality and are continuing preparations in anticipation of further cases.
