The DUP leader, Ian Paisley, has said the Dublin government's desire to hold a referendum in the 26 Counties on citizenship is a breach of the 1998 Good Friday Agreement and further evidence that it is dead.
The referendum, set to take place on June 11th alongside the local and European Parliament elections, would take away the automatic right to citizenship from children born here to non-Irish nationals.
It would amend the right to citizenship embodied in the existing Articles 2 and 3, approved by the people of the 26 Counties in a referendum in 1998 on the Good Friday Agreement.
Dr Paisley pointed out that the move was a unilateral change and showed the agreement could be further amended as demanded by unionists.
``Anyone who argued that the Belfast Agreement could not be changed has clearly been proven wrong by the actions of the Dublin Government,'' he said.
``In holding a referendum to amend Articles 2 and 3 of the Irish Constitution the Irish Government are unilaterally amending the 1998 agreement.''
The British government has previously made a number of unilateral changes to the Agreement, passing legislation to suspend the Stormont Assembly and to delay required Assembly elections.
He continued: ``In November the unionist people voted for a new agreement. The referendum in the Republic of Ireland in June proves that the agreement is not set in stone and that change is inevitable.
The Opposition parties are to join together in the Dublin parliament next week in an attempt to persuade the Government to refer the citizenship referendum to a committee on the Constitution.
It has been criticised by the Opposition and by human rights bodies, who fear the referendum campaign may take on a racist tone.
Fine Gael, Labour and the Green party said in a statement today they will will try to persuade the Government to refer the proposed amendment to the All-Party Oireachtas Committee on the Constitution. The referendum is also strongly opposed by Sinn Féin, the Socialist Party and independents.
Dublin has so far refused to consult the Human Rights Commission or the opposition parties about its citizenship referendum plans, despite widespread fears over the ramifications of the proposal.
Meanwhile, a former US congressman, Mr Bruce Morrison, who won 48,000 green cards for Irish ``illegals'' in the US in the 1980s, has questioned the Government's approach.
He said he doubted that the referendum was necessary to protect the integrity of Irish citizenship. ``I am not sure what that means. People in the US who can trace a grandfather back to Ireland can qualify for Irish citizenship. What is this really about?'' he asked.
``People will use to some extent to their advantage the rules that are in existence in the world. I do not think that you should build a citizen/immigration policy on the cases where people use laws to their advantage.
``Once people have settled here for months or years nobody is going to allow you to remove them. Deterrence is the key. The Irish immigration system is hopelessly inefficient.
``Should asylum-seekers be allowed to work? Many of these people are capable of supporting themselves, rather than needing public support. I think that that is perverse,'' said Mr Morrison.