Mr Caoimhghin O Caolain (SF, Cavan-Monaghan) indicated that he would abstain in the Dail vote on the legislation and warned against "euphoria and overblown claims" about the significance of the agreement.

"Very important decisions have to be made about the future of this country by all of us in the weeks and months ahead. Sober judgements need to be made and the electorate needs to be provided with comprehensive information on all the implications of their votes in these referendums."

He said that his party did not regard the Good Friday document as a settlement. "But we do believe that the new political scenario which it creates can provide a basis for advancement."

Mr O Caolain said there could never be a return to the days of unionist one-party rule, backed by the British government, or to the days when the people of Ireland and Britain, but most particularly the people of the Six Counties, were caught up in a cycle of repression and resistance and when, on the British side, those with a military agenda, the "securocrats", determined British government policy.

The expectations of all true democrats in Ireland were high, he said. "The disbandment of the RUC and the emergence of a new policing service, the release of all political prisoners, the demilitarisation of the Six Counties and the withdrawal of the British army, the end of sectarian discrimination in employment, the repeal of repressive legislation, full and equal status for the Irish language - these are now awaited and demanded."

There was, said Mr O Caolain, real and justified concern throughout nationalist Ireland about the implications of the proposed constitutional change in the Republic.

"For many years, some in this House have campaigned for the dilution of Articles 2 and 3, even without any peace process and without the remotest prospect of an agreement. Sinn Fein has consistently opposed the removal of the definition of the national territory or the incorporation of the unionist veto in the Constitution.

"We sought maximum change in British constitutional legislation and a strengthening of the Irish constitutional imperative to unity. The proposed incorporation of consent into Article 3 presents a major difficulty. Consent here, once again, is unarguably the unionist veto in disguise."

Mr O Caolain commended the initiative of the IRA, which allowed the peace process to evolve and then to revive. The IRA had "the courage to persevere, and credit is due to them as much as to any of the participants in the peace process".

The former Tanaiste and Labour leader, Mr Dick Spring, said he hoped that Sinn Fein and the leadership of the party would support the referendums.

"I have welcomed the fact that Gerry Adams and Martin McGuinness have given a new direction to Sinn Fein in recent years. It is now time to support this agreement in an unequivocal way in both parts of the island, and the sooner that the Sinn Fein leadership gives clear directions to their supporters the better for the process."

He said he found remarks by Mr O Caolain on radio on Monday "absurd and unsustainable". It was not credible to participate in an inclusive negotiation process for many months, to welcome its conclusions, and then suggest different strategies for supporters in the North and South.

"I do hope that clear and consistent leadership will be given on this sooner rather than later. We certainly did not get it at the weekend at the Sinn Fein ardfheis."

Mr Trevor Sargent (Green Party, Dublin North) said that balanced constitutional change was always a requirement of a just settlement in the North. The Green Party had been calling for changes to Articles 2 and 3 in tandem with changes to UK legislation since the party's foundation in 1981.

He said that the creation of a power-sharing assembly was a logical component of any agreement likely to gain the support of the people. The model on offer was a serious attempt to get beyond the politics of simple majoritarianism.

The North-South bodies must not be looked upon as Trojan horses, said Mr Sargent. "At the moment they represent two quite different things to the two larger communities in the North. For the nationalists, they are the practical expression of their Irish identity." The Minister for Foreign Affairs, Mr Andrews, said that the first truth to be celebrated was that the agreement had happened. "Set against the background of 30 years of conflict and of previous difficulties in forging a settlement, this is an immense achievement in itself."

He said that the difference in the respective constitutional and legislative provisions meant that the wordings of the questions North and South, and their precise legal effects, were different. "But in their broad political implications they are exactly the same. The agreement was agreed as a totality, and it will stand or fall as a totality."

The Minister of State for Foreign Affairs, Ms Liz O'Donnell, said there was no need for Irish people to be the prisoners of the past.

"For too long, even as our culture was celebrated and our economic advances hailed, the name of Northern Ireland evoked, across the world, visions of bitter conflict."