Sick days taken by public sector employees cost taxpayers nearly €320m last year.
Nine sick days were taken, on average, by each public sector employee, new figures show.
Dublin Independent TD Finian McGrath told the Herald that the substantial costs involved are a major worry.
"I'm concerned about the costs," he said. "We need to keep reforming our public service and ensure that we get the maximum support for these reforms.
"But also, we have to ensure that people who are genuinely sick are always looked after."
The latest figures from the Department of Public Expenditure and Reform show that the average public sector worker took 8.7 sick days in 2014, down from 9.5 in 2013, with civil servants taking almost twice as many sick days as teachers.
On average, teachers and members of the Defence Forces took fewer than six days off last year due to illness.
Those employed by government departments and agencies took, on average, 10.1 sick days last year, according to the figures. This cost the Government €43.7m in 2014.
The figure for civil servants, though, was less than a third of the €150m required to cover the 9.6 sick days taken by those working in the public health sector.
The total cost of sick leave across the public service for last year was €319.3m, a decrease of almost 14pc compared with 2013.
These official numbers relate to 245,000 Full-Time Equivalents (FTEs) across the public service, including the civil service, local authorities and the education, health, justice and defence sectors.
The total number of sick days taken works out at around 2.13 million.
The 2014 statistics represent the first detailed information available since the introduction of the Public Service Sick Leave Scheme last year.
This, the Government claims, has effectively halved paid sick leave for public sector staff, saving more than €51m last year and reducing the rate of sick leave to 4pc.
Under the new scheme, staff are allowed a maximum of 92 days on full-pay for an illness or injury.
After that, they are then allowed a maximum of 91 days on half-pay in a rolling one-year period to a maximum of 183 days paid sick leave over a four-year period.
On account of this reduction, the Department of Public Expenditure and Reform said there were, approximately, an additional 260,000 days worked by public servants last year compared with 2013.