Hundreds of international delegates at the second day of a conference in Belfast heard Mr Seamus Mallon stress that key decisions in the Northern peace process needed to be taken now.
The State of the World Forum, which convenes in Dublin today, also heard from the chief commissioner of the Northern Ireland Human Rights Commission, Mr Brice Dickson, that his commission was "actively exploring" the possibility of UN rapporteur Mr Param Cumaraswamy being appointed independent supervisor of the investigation into the murder of solicitor Ms Rosemary Nelson.
Other speakers at yesterday's session of the forum included Mr Lech Walesa, Poland's president from 1990 to 1995.
No more blood should be shed over the drawing or redrawing of borders in Europe - that was the challenge to this generation, Mr Walesa said. "There should be no new borders and it is our goal to eliminate borders."
Introducing the plenary session on the vision of European integration, Mr Mallon, the North's Deputy First Minister, said that as in the formation of the European Union, certain decisions in an evolutionary process could be left to the next generation. "So with the Good Friday agreement certain decisions can be left to future generations. But key decisions must be taken now".
He said the European elections, Drumcree, and the publication of the Patten report on policing at the end of summer, would not make taking decisions easier.
In a later session on human rights, the 1996 Nobel peace laureate, Mr Jose Ramos-Horta of East Timor, said the real threat to world peace and security was from poverty.