Sinn Fein President Gerry Adams has attacked the 26-County political establishment for failing to support his party's motion in support of a united Ireland.
The motion calls on the 26-County Government to draw up a Green Paper [discussion document] to prepare for the political, social, economic and cultural unification of the island and to engage in dialogue with unionists.
Outside the gates of Leinster House parliament in Dublin, Mr Adams said he could not understand the lack of support from the Dublin government and opposition parties.
"For the life of me, why these parties which have as stated policy positions the objective of Irish unity, cannot support this motion, it's beyond me," he said.
The five Sinn Fein TDs secured private members' time to debate the motion in the Dail tonight, but the lack of support from other political parties means that it is unlikely to pass.
The party's leader in the Dail, Caoimhghin O Caolain, called on all political parties to unite behind the idea to make it a reality.
"People are talking about the symbolism of a united Ireland for the centenary of the 1916 Easter Rising in 2016 but I believe it should be achieved as soon as humanly possible. I hope to see it in my lifetime," he said today.
"The political situation has changed enormously and there will also be huge changes in the decade before us."
The motion, published today, calls for the promotion of all-Ireland policies and strategies and highlights the need to persuade unionists on the advantages of unification.
It also says the Government must "prepare politically, economically, socially and culturally for Irish unification; identifying measures, including a Green Paper, which can assist a successful transition to a united Ireland".
Mr O Caolain pointed out that Fianna Fail is known as the republican party and Fine Gael described itself as "the United Ireland Party" when it was first founded in 1933.
The motion was debated on Wednesday evening and will conclude on Thursday evening during the party's Private Members' time.
Mr O Caolain, who is into his ninth year as an Opposition TD, also told a media briefing today that it was inevitable that Sinn Fein would soon enter into a coalition government and that its TDs would become ministers.
"At some point in time, that is a nettle that Sinn Fein will have to grasp.
"If Sinn Fein is to go from effective presentation of its policies to effective implementation, we will need to go into government at some point."
The Cavan/Monaghan representative denied Opposition claims that the issue of speaking rights for Northern MPs in the Dail was a "side deal" cut between Sinn Fein and Taoiseach Bertie Ahern. FIne Gael and Labour have strongly opposed the proposal.
"All we're arguing for is the right for MPs to actively participate in debates in the Dail chamber on issues that affect them or they have specialist knowledge of. I do believe it should happen.
"It would promote positive engagement and dialogue between north and south politicians and would demonstrate the type of society we are trying to create on this island."
He said Sinn Fein also eventually wanted to see voting rights accorded to northern representatives.
* Meanwhile, it was reported that a large scale memorial to the struggle for Irish independence is to be built on the site of the 1916 Easter Rising in Dublin as part of the Dublin government's efforts to reclaim the votes of Irish republicans.
It was reported that Bertie Ahern's government intends to start planning soon for the 2016 commemoration with the centrepiece being the development of the large site behind the GPO Post Office on O'Connell Street, which was the headquarters of the Rising.
Ministers are said to have in mind something along the lines of 'Les Invalides' in Paris, which contains Napoleon's tomb.