The shortage of consultants across the HSE has resulted in more shifts being filled by medics on locum contracts.
The reliance on temporary consultants to fill vacant posts has raised concerns over continuity of care, said Fine Gael TD Colm Burke, a former junior minister in health.
Figures released by the HSE show there were 763 locum doctors in consultant positions in Ireland working across all specialities as of last October. The figure equates to 16.5 pc of consultants employed in the health service.
Mr Burke said: “Existing consultants have expressed concern to me that departments with an excessive reliance on locum staff affects delivery of patient care through disruption in continuity of care and team morale.”
The TD obtained the figures in response to a parliamentary question.
They show that the shortage of permanent consultants is most acute in the areas of medicine and psychiatry.
The largest number of locum consultants employed was in the specialities of medicine (236) followed by psychiatry (141) and surgery (101).
The HSE Dublin Midlands employed 166, the highest of all health service regions.
The HSE West and North West ranked second, with 143 locum consultants covering hospitals in Letterkenny, Mayo, Sligo and Galway.
Cork University Hospital, with 51, and Galway University Hospital, with 50, had the greatest reliance of any hospital on locum consultants.
In Galway, 50 locum consultants worked on temporary contracts, with 16 of those in surgery and 11 in medicine.
The figures also showed the strong reliance of regional psychiatric services on locum consultants.
Galway/Roscommon Mental Health services were staffed by seven locum consultant psychiatrists, while Donegal Mental Health services had five.
Ten locum consultant psychiatrists worked for Louth Meath Mental Health Services and 16 for mental health services across Cork and Kerry.
Smaller regional hospitals reported a notable reliance on locum consultants.
These included Letterkenny, with 27 locums, Tullamore, with 26, Tralee with 32 and Tipperary 15.