Opposition parties have called on the Taoiseach to respond to allegations that he and his partner Ms Celia Larkin apparently used the State guesthouse in Phoenix Park to host a private party.
An article in today's Sunday Independent claims Ms Larkin held a private party at Farmleigh, the former Guinness family home, last Christmas at which guests were given a tour of the State rooms as well as hospitality of mulled wine and mince pies.
But Fianna Fáil says all that was involved was a tour of the house and that opposition politicians have been accommodated in similar fashion.
However Fine Gael's Ms Nora Owen said this is another example of Taoiseach's "arrogance" and called on Mr Ahern to make a full statement.
Labour's Ms Joan Burton said: "This disclosure is the latest manifestation of the growing arrogance in Fianna Fáil party."
"When a Taoiseach believes state property can be used as his personal party centre, then it is an indication that he has spent too long in office," she said.
The Office of Public Works, which is in charge of the house's maintenance on behalf of the taxpayer, have said the function was "not an official event".