The building in Dublin Castle where the Mahon Tribunal held its public hearings is to be converted into a conference facility for Ireland's EU Presidency - at a cost of €3m.
Minister of State Brian Hayes said the overall cost of Ireland's presidency, in the first half of next year, would be around €60m - a third less than was spent in 2004 when Ireland last hosted the presidency.
The minister said savings are being made even though the number of countries has expanded from 17 to 27.
He said security and other costs would be reduced by centralising meetings in Dublin and added that the new facility could be used for cultural and other events in the future.
The Mahon Tribunal held its public hearings in the Printworks building.
Last year the venue was also used as a media centre during the visits of US President Barack Obama and Britain's Queen Elizabeth.
Under the Office of Public Works plans, the entrance of the building - the scene of hundreds of witnesses arriving for the Mahon Tribunal - will become a service entrance.
The main entrance of the new conference facility will be through the Stamping building, the ground floor of which will also be converted.
Revenue staff on this floor will move to another part of the castle.
Fianna Fáil's Finance Spokesperson Michael McGrath said hosting the EU presidency has to be seen as a good opportunity for Ireland.
He added that given the hardship facing people, there is no need for any extravagance and costs should be kept to a minimum.
Work is due to begin in July.