Irish unity must be more than an aspiration and an objective, Sinn Féin's leader in the Dáil Caoimhghín Ó Caoláin told the House.
During his party's Private Members' motion calling for unity, he said that re-establishing the structures set up under the Belfast Agreement was the immediate task for the British and Irish governments.
"On the part of the DUP there can be no more possible excuses for non-engagement with Sinn Féin," he said. "The excuse of IRA weapons is no longer tenable." .
Sinn Féin's justice spokesman Aengus Ó Snodaigh, speaking in Irish, said that his party's vision for a united Ireland "has its foundations in the 1916 Proclamation and the 1919 democratic programme which enshrine our core values".
However other Opposition parties said the debate was a political battle between Fianna Fáil and Sinn Féin to consolidate their positions.
Sinn Féin's motion calls for the preparation politically, socially and culturally for Irish unification; identifying steps and measures, including a Green Paper, that can assist a successful transition to a united Ireland".
The Government, Labour and the Green Party all introduced amendments to the motion. The Government motion expressed its "full support for the ongoing efforts of the two governments to bring to completion the full implementation of the Good Friday agreement".
Mr Ó Caoláin criticised what he called the playing down of the legitimate political demand for Irish reunification for fear of offending unionists.
"Whittling down the agreement, failing to implement it or abandoning the legitimate political objective of Irish unity will not encourage dialogue. On the contrary it will reinforce intransigence."
Mr Ó Snodaigh said he welcomed the Taoiseach's announcement that State commemorations of the 1916 Rising were to be introduced and urged him to "use the occasion to reflect seriously on the values and goals of the signatories and on how these contrast so sharply with the record of successive governments, including his own".
Martin Ferris (SF, Kerry North) hit out at the Labour Party. He said the vast majority of Labour supporters wanted a united Ireland, but party leader Pat Rabbitte and others wanted to "engineer a permanent settlement in which the six counties remain forever under British sovereignty". He said Sinn Féin had "far closer and more genuine links with members of the unionist community than either himself [ Rabbitte] or anyone else in the State".
Green Party leader Trevor Sargent said he did not blame Sinn Féin for "rushing this particular fence" given that Fianna Fáil was reclaiming 1916 for its own political purposes. He said the Greens were unique in that they did not trace their origins back to "violent revolution".
Minister for Agriculture Mary Coughlan said the Government's amendment "underlines the simple fact that in order to rebuild the institutions of government, we must first rebuild confidence and momentum in the political process".
She said the "constitutional balance struck in the agreement is a careful and sensitive one. It underlines the legitimacy of seeking a united Ireland. It also recognises, however, that it is the current wish of the majority of people in Northern Ireland to remain part of the United Kingdom. Most importantly, it clearly and unequivocally enshrines the principle of consent".
Fine Gael's foreign Affairs spokesman Bernard Allen said the debate was an opportunistic and posturing "power play" by Fianna Fáil and Sinn Féin to consolidate their political position.
