The Health Service Executive overspent its budget by €164m by the end of May, according to its latest performance report.
It represents an increase of €28m on the April figure.
Around €95m of the overrun was in the acute hospitals and social services areas.
The balance of €69m was due to extra spending on primary care services, local schemes, State claims, overseas treatment and pensions.
The report also says that the number of people attending emergency departments reduced in May compared to April.
