The Taoiseach should draw up a plan for Irish unity as soon as possible, Gerry Adams has said.
The Sinn Fein leader was addressing a Dublin conference on bringing both parts of the island together.
The Louth TD urged Enda Kenny to begin work on a new constitution and other measures.
"Real social, economic and political change is not easily achieved but all those who have a genuine commitment towards building an Irish republic worthy of the name must work together towards that end," Mr Adams said.
Among speakers at the conference were former Ulster Democratic Party member David Adams, the Rev Gary Mason from East Belfast and former Lebanon hostage Brian Keenan.
Mr Adams delivered the main address, calling on the Taoiseach to commission a Green Paper on Irish unity which would address all aspects of this "national and democratic" project, including its political, social, economic, cultural, legal, administrative and international dimensions.
The former West Belfast MP said a joint Committee of the Oireachtas on Irish unity should monitor, assess and report progress on the Green Paper's implementation.
He called for an end to duplication of services north and south and said a federated Ireland could be part of the solution. Mr Adams stressed that the views of unionists needed to be taken into account.
There should be a new constitution - discussed, debated and agreed by all on this island, which would enshrine citizens' rights in law, he said.
"Citizens north and south are looking for something new," he said.