Sinn Féin has said it would call on voters to reject a new EU constitution based on the draft produced by the Convention on the Future of Europe.
The party's chairman, Mr Mitchel McLaughlin, said it would advocate a No vote against any constitution that was designed as an enabling mechanism for the creation of an EU superstate.
At a briefing in Dublin, he said: "Our reading of the leads to believe that the ongoing process of a developing economic and military superpower emerging will be sped up by ratifying an EU constitution."
While Sinn Féin agreed that the existing EU treaties should be simplified and consolidated, Mr McLaughlin said that the party did not accept the argument that the EU needed a constitution.
Mr McLaughlin said the draft constitution gave the EU a legal personality for the first time and said that this would only diminish the sovereignty of member-states.
However, Mr McLaughlin said there were positive aspects to the draft, among them plans for a charter of fundamental rights. He also praised the commitment to eradicate poverty.
Mr Aengus Ó Snodaigh TD said that the draft would support the progressive militarisation of the EU.
He said the document left the way open for the authorisation of pre-emptive attacks, such as the war against Iraq.
Mr Ó Snodaigh said that any new constitution should protect the neutrality of states such as Ireland and the primacy of the UN.
He said this could be achieved through the insertion of a specific article "explicitly recognising the rights and duties of neutral states with the Union and explicitly recognising the right of those states requiring a UN mandate for military operations".
The Sinn Féin candidate in Dublin for the European Parliament next year, Ms Marylou McDonald, said that the draft constitution was part of a drive to create a world superpower out of the EU.
The draft would establish EU law as superior to national law. Ms McDonald added: "While the word 'federal', which appeared in earlier drafts of the document, has been removed, this in effect creates a federal state in which federal law, in more and more areas, overrides the laws of member-states."
She criticised the absence of "national sovereignty" and "national self-government" from the article concerning "national identities" and "regional and local self-government".
