Unionists should embrace the Republic's new Constitutional Convention, Gerry Adams says.
The Sinn Fein leader told the forum's inaugural meeting at Dublin Castle he hoped the DUP and Ulster Unionists would see the value of taking part in the year long debate. Mr Adams said: "We should continue to try and persuade them to participate."
The Constitutional Convention was set up to consider changes to the 1937 Constitution of Ireland.
It will meet almost every month in 2013 to discuss and make recommendations on issues such as the length of the presidential term, reduction in the voting age, electoral reform and provisions for gay marriage.
The convention is made up of 33 TDs and 66 ordinary citizens who were randomly selected as a representative sample by a polling company. Places are also available for participants from the Northern Ireland Assembly.
Mr Adams, who represents Louth in the Dail, described the convention as limited but said his party had put a number of items on the agenda including voting rights in presidential elections for Irish passport holders living north of the border.
Mr Adams said a new political dynamic had been created by the 1998 Good Friday Agreement and claimed constitutional reform could help build further reconciliation.
He said: "Sinn Fein is for a constitution that embraces all of the citizens of this island especially those who feel themselves to be British. A constitution which builds reconciliation between Orange and Green. A constitution that is part of shaping a new Republic for the 21st century."
Taoiseach Enda Kenny said: "The Good Friday and the St. Andrews Agreements are fundamental to the changed relationships on the island of Ireland and between Ireland and Britain.
"It is absolutely right not merely correct that elected representatives from Northern Ireland should be part of the Convention and that the Convention itself, in carrying out its work, should have due regard to the principles enshrined in the Agreements. The Convention must be representative of Irish society generally, and not just particular viewpoints."