The Government should reassure the unionist parties, publicly as well as privately, that they were not up against a pan-nationalist alliance led by Sinn Fein in the forthcoming Belfast negotiations, according to Mr Sean Donlon.
He added that the Fine Gael leader, Mr John Bruton, was correct in stating that it was the unionist people, not the British state, which was the real British presence in Ireland.
The former secretary of the Department of Foreign Affairs was giving the address at the annual Beal na mBlath Michael Collins commemoration.
Mr Donlon also said that it was important that the republican movement clarified its stance on the principle of consent.
"In the forum for Peace and Reconciliation Sinn Fein did not find it possible to join with all the other parties represented there to form a pan-democratic alliance," he said.
"They did, however, appear to indicate that their difficulty was not with acceptance of the principle of consent but with the timing and circumstances in which they would formally accept it.
"Sinn Fein has urged the leaders of unionism to open their minds to the possibilities created by the Belfast negotiations. Nothing would be more conducive to opening unionist minds than the acceptance by Sinn Fein of the principle that there can be no change in the status of Northern Ireland without the consent of the majority of its people. Michael Collins, when he ruled out the coercion of the unionists in Northern Ireland, was the first to articulate that principle."
Earlier he praised Collins as a military genius, a politician, an organiser, a negotiator and a visionary of moral courage.
The year of his death, 1922, was a year of extraordinary tragedies for Ireland, which lost Arthur Griffith 12 days before the assassination of Collins, he said. But it was also a year of great achievements.
"Subsequent events have shown that the major political decisions taken in 1922, including many inspired by Michael Collins, were the correct ones."
Unlike earlier revolutionaries, Collins paid great attention to detail. Mr Donlon credited his training in the bureaucracy of the British Post Office, the Guaranty Trust Company of New York and with accountants Craig Gardner for this.
Yet his many achievements in his short period in office left unfinished business, notably Northern Ireland, according to Mr Donlon.
He quoted John Hume's emphasis on the divisions between the people, rather than the territory, of Ireland, adding: "For the first time since the foundation of the State there is a real possibility that the divisions can begin to be healed."
If the remaining obstacles were overcome, the forthcoming negotiations in Belfast would be the most inclusive talks on the future of Ireland ever held.
He praised the work done by Albert Reynolds and John Major, then John Bruton and John Major and most recently Bertie Ahern and Tony Blair, in bringing the talks to this point.
There were a number of encouraging elements in the backdrop to the talks, he said.
These include the statement in the Joint Framework Document that the British "have no selfish or strategic or economic interest in Northern Ireland"; the confirmation of their support for the principle of consent from all recent Irish governments; the reinstatement of the IRA ceasefire; the international support for the process; and the decision by the Ulster Unionist Party to enter into pre-negotiation consultations with a wide range of opinion.