Public servants are only re-hired "in very unusual circumstances" after they retire, according to Jobs Minister Richard Bruton.
He said that four retirees recently taken back on in his department had "largely voluntary-type roles" and were not paid very much.
He defended the Government's policy on recruiting former state employees, without advertising the positions, when tens of thousands of people are on the dole.
His comments come after it emerged that senior civil servants, who retired before the end of last February to get a bigger pension, are back at work.
The most recent figures, show the last government spent over €15m on re-hiring retired public servants during 2010.
"Clearly that would only happen in very unusual circumstances," Mr Bruton said.
"Most of the cases that have happened, it's only for very short periods where someone has been brought in to allow an orderly recruitment of people for the future."
He said the Government is determined to reduce the size of the public service and early retirement schemes had been offered for this reason.
"There are adjustment periods and sometime it's necessary to temporarily have replacements," he said.
"Each of those cases is overseen very carefully by the Department of Public Expenditure and Reform and its objective is to manage the public services effectively, to get best value, to reduce and deliver more from less."
He said each re-appointment is carefully examined before the Government would allow it.
"I do know that in the instances that I have seen, and I haven't seen all departments, they're either very temporary or they're situations perhaps where someone is in a voluntary capacity," he said.
"They're playing a role, doing a small task which is just drawing on their experience but it's not an employment as such."
There is no central log of the numbers of retired staff who were brought back to work across the public service last year.
The Health Service Executive has produced figures that show it re-hired 686 retired health staff at a cost of €11.6m.