The Taoiseach condemned a telephone call to RTE radio made by an official in the Government Information Services (GIS) pretending to be an ordinary member of the public.
The matter was raised by the Fine Gael leader, Mr Enda Kenny, who referred to an incident in which Mr Ben Dunne, a civil servant, telephoned the Gerry Ryan radio programme in support of Mr Ahern's handling of the Flood tribunal report.
The Taoiseach said it was totally improper for the individual to do what he did.
"It was totally against the rules and ran counter to the impartiality of the Civil Service. To the best of my knowledge, the individual acted on his own behalf and has stated so," he said.
"He has been contacted in writing, and, in accordance with Civil Service regulations, he has a period in which to furnish a reply before the disciplinary hearing."
Asked about the Government's communications unit, Mr Ahern said that it had six staff members, all of whom were civil servants.
Five were on secondment from other Departments, and one staff member was from his Department.
A seventh member of staff had transferred to the Department of Social and Family Affairs last January, and no replacement had yet been appointed.
The total projected cost this year was €262,505. The unit provided a media information service to Ministers and their Departments.
It furnished news updates and transcripts which ensured that Departments were kept informed in a fast and efficient manner of relevant news developments.
It was conservatively estimated that in a full year it saved Departments approximately €175,000 he said.
Mr Ahern said the information supplied by the unit had been sought under the Freedom of Information Act on numerous occasions.
It had formed the basis of a detailed reply to a parliamentary question quite recently.
Therefore, the information produced by the communications unit was in the public domain, he added.
