Taoiseach Micheál Martin has said a Border poll is not on the agenda for his Government in the next five years.
He was speaking at Dublin Castle at the launch of the Shared Island Initiative. The project has seen €500m ring-fenced for investment in North-south initiatives.
The Taoiseach sought to ease unionist fears that the unit would serve as a "stalking horse" for a united Ireland.
"The Government has said that, for the next five years, a Border poll is not on our agenda," he said.
"I've also made it clear that my approach is through consensus and listening and engagement."
Mr Martin said scoping would begin on the viability of high-speed cross-Border rail links and that progress is overdue on the A5 transport corridor, the Ulster Canal and the Narrow Water Bridge.
"We will be working closely with the Executive to seek to move ahead with full delivery, without undue delay," he said.
He insisted that the development of the Shared Island Unit would not affect anyone's identity, adding that the logic of sharing resources on the island was "obvious".
He also pointed to the 1.3 million people who have been born on the island of Ireland since the Good Friday Agreement was signed, and urged them to contribute to the dialogue.