SDLP leader Colum Eastwood has said the party will consult with unionists on its proposals for a "united, just and reconciled new Ireland".
The SDLP is to set up a forum where people and communities will discuss future constitutional arrangements on the island.
Mr Eastwood said the New Ireland Commission will look to engage with every community, sector and generation to develop new proposals that will "unite people across the island".
The Foyle MP said the work will be challenging and will demand "we stretch ourselves again" to accommodate all communities.
Private conversations, he said, were under way with people from different areas of unionism.
"It's important those discussions are quiet at the moment and are allowed to be had in that space," he added.
Mr Eastwood said the "only path to uniting the people of this island" was through the spirit of partnership, co-operation and reconciliation that the Good Friday Agreement is built on.
He added: "Delivering a new Ireland demands that we all spill our sweat to forge new enduring relationships between the people of this island and that we demonstrate to everyone that there is an equal place for them.
"The SDLP's New Ireland Commission will seek to engage with every community, sector and generation on this island to build new proposals that can generate a consensus on our future constitutional arrangements.
"This work will be challenging, it will demand we stretch ourselves again to accommodate our communities in all their difference and diversity but it is, ultimately, necessary that we plot a course through the immense period of change we're living through.
"Leaders in the SDLP worked hard to forge a consensus for peace that would allow everyone to pursue their own constitutional ambitions free from the threat of violence. This new generation of SDLP leaders is prepared to spill our sweat again to create a path toward a united, just and reconciled new Ireland.
"We are in dialogue with significant individuals and quiet conversation with a number of communities to secure further confidence in our plans."
He said further announcements on the commission panels will follow over the summer.