The General Post Office on O'Connell Street in Dublin will cease to be used by An Post and will be converted into a national monument.
Under plans being drafted by the Government, the GPO would become the memorial for the 1916 Easter Rising, along with other aspects of the State's history.
Last night, a Progressive Democrats spokesman for the Minister for Justice, Michael McDowell, said the GPO "would cease to be an office block and post office" in time.
The GPO's main hall would become the entrance to the memorial, leading onto a rotunda, he said. Mr McDowell has said that both he and Minister for Finance Brian Cowen believe the GPO should "have a more historic purpose".
Mr McDowell's spokesman denied comparisons made in the Sunday Tribune yesterday between the Government's plans and Napoleon's tomb, Les Invalides, in Paris.
Minister of State for Justice Brian Lenihan said the Government would commemorate the men and women of the 1916 Rising next year.
Fine Gael Dublin MEP Gay Mitchell said Fianna Fáil and the PDs were attempting to "hijack" 1916 for "narrow political purposes". "The Taoiseach should not be using his role of president of Fianna Fáil to make announcements about the defence forces participating in a new Easter parade to commemorate 1916.
"While Louis XIV once said that 'L' état c'est moi', the FF/PD partners in Government now seem to be suffering under the same delusion. But Fianna Fáil and the PDs are not the State.They have no right to manipulate the State, the centenary of 1916, or its Defence Forces for party political purposes. It is worth recalling that in 1916 de Valera served in Boland's Mills while Collins, Cosgrave and Connolly all served in the GPO," he said.
"The political parties representing the continuation of the tradition of these men should be part of the process in deciding how the vicinity of the GPO, the centenary itself and the years leading up to it are marked," Mr Mitchell said.