The constituency office of the Taoiseach makes an average of 300 representations on behalf of constituents every week.
Senator Cyprian Brady, who runs Mr Ahern's constituency office, St Luke's, said yesterday that, while the letters are usually signed in the Taoiseach's name, Mr Ahern does not see or approve most of them himself before they are issued on his behalf.
Senator Brady told RTÉ news that in the normal course of events representations were stamped with the Taoiseach's signature.
"It would have been processed through our constituency office and have been issued from there," he said.
He usually briefed the Taoiseach on constituency matters and representations each morning. However, he could not say whether he had informed the Taoiseach about the representation on behalf of Mr Brian Murray.
"We deal with quite a volume of representations across a huge range of areas, and that would have been one of many representations and issues we dealt with.
"We would be going through a raft of different issues, so I can't categorically say whether I did or I didn't," he said.
The Taoiseach's constituency operation is one of the most efficient and busiest of any in the State. Representations by the Taoiseach have caused controversy before.
In May 1999 it emerged at the height of the Philip Sheedy affair (which led to the resignations of two judges) that Mr Ahern had made representations to his colleague, the minister for justice, Mr O'Donoghue, that day-release be given to the jailed architect.
The controversy caused considerable tension between the Taoiseach and his government colleagues, the Progressive Democrats.
On the eve of the 2002 general election, the Progressive Democrats found themselves at the centre of a major controversy when it emerged that the junior minister at the Department of the Environment, Mr Bobby Molloy, had made representations on behalf of Patrick Naughton to the Department of Justice before he was convicted in April 2002 of raping his daughter.
He subsequently resigned over the affair, just weeks before he was due to retire from politics.
A considerable amount of public funds are also used in maintaining the constituency machines of Ministers.
In 2002 Ministers spent 12.5 million running their departmental and constituency offices.
An estimated 100 civil servants are employed specifically to deal with constituency matters.
For example, the Tánaiste, Ms Harney, employs three people at her constituency office: a personal secretary, personal assistant and staff officer.