The Health Service Executive has overspent by €432m in the first nine months of this year - almost €1.6m every day.
The HSE says it is on track to overspend by around €510m - but it is in talks to try and reduce that amount.
Part of the overspend is down to a 42% increase in its spending on agency staff - which comes in spite of increasing numbers on the HSE's own payroll.
It has also revealed a growing problem with waiting lists - saying the number of adults waiting eight months for an appointment has increased by 11% in just one month.
Earlier today, a leading analyst said Ireland's health service has suffered "the biggest impact" from austerity across the whole of Europe.
Dr Stephen Thomas from Trinity College's Centre for Health Policy and Management made the remarks at an all Ireland Conference on Mental Health and Addiction.
He says the public has suffered a "triple whammy" - with more people needing healthcare as services and access to treatment get scaled back.
Dr Thomas says the focus now needs to be on services for the most vulnerable people - while looking towards Free GP care in the long term.
However, he says the HSE will need to come back from unprecedented cuts.