More than 45 groups have combined to urge a No vote in Friday's citizenship referendum.
In a joint statement, the groups - including trade unions, political parties and immigrant-support groups - said that in the weeks of the brief referendum campaign there had been one consistent factor - the repeated emergence of voices of civil society calling for a No vote.
"There have been voices from children's organisations, voices from women, voices from migrants - Irish and non-Irish - voices from churches, lawyers, doctors, communities, human rights groups and more," the statement said.
The groups said they had united to remind people what the "real issues" about the referendum are.
They said these include the question of whether there should be equal citizenship at birth for all children, or whether that right should be withdrawn from some children in Irish history. They also questioned what the impact of the referendum would be on the rights and welfare of future children born in Ireland.
The alliance also questioned what the implications would be for Northern Ireland of "overturning" the vote of almost 95 per cent of the Irish people in 1998 to protect equal citizenship rights in the Constitution and to pass the Belfast Agreement.
Mr Owen Keenan, chief executive of Barnardos, said this was a referendum on the rights of children.
Barnardos Chief Executive Mr Owen Keenan
"We are deeply concerned about the referendum's implications for children. We are not satisfied with the explanations offered by Government spokespersons and believe that it is fundamentally unsound to hold the referendum at this time.
"The government does not seem to have carried out any impact assessment on whether this referendum is in the best interest of children in Ireland, despite the fact that Government policy obliges the Government to do so before taking any major decision or action with significant consequences for children."
Ms Inez McCormack, the first female president of the Irish Congress of Trade Unions and a former-member of the Northern Ireland Human Rights Commission, said the right of all born in Ireland to be citizens - without discrimination - was a key part of the Belfast Agreement.
"The Government now wants to remove that right from children without even the voices of those who negotiated the Good Friday Agreement, and the voices of those in Northern Ireland who voted for it, being heard."
She said to remove that right now made a "mockery" of the people who worked so hard for the Agreement.
The groups which have signed up to the campaign for a No vote include the AGTWU, the Children's Rights Alliance, Communities Against Racism, Doctors Against the Amendment, and the Irish Council of Civil Liberties.