The Foyle MLA said: “The seriousness of this moment can’t be naively dismissed or diminished.
“It is important for all of us to understand that this isn’t just one more turn in the cycle of failure which has now gone on for the last 13 months.
“Instead all of us are being faced with the prospect that the cycle of negotiations now ends and that power is handed over to a Tory/DUP Government in Westminster. We are being faced with the prospect and threat that all decisions on the governance of Northern Ireland are to be made by a Tory/DUP committee in London.
“That scenario is cause for deep concern and worry, particularly for northern nationalism which has been left powerless after this failed negotiation. It is a scenario which runs against everything imagined, won and endorsed in the Good Friday Agreement. It is a scenario that only rewards the DUP.
“That is why it is a scenario that simply cannot be allowed to happen.
“In the absence of ongoing negotiation to restore devolution, I have said that the first step must be the formation of the British Irish Intergovernmental Conference.
“That is the first step outlined in the Good Friday Agreement – there is no logic or reason why that should be resisted.
“I have spoken to An Tánaiste and to Leaders of Fianna Fáil and the Labour party in order to build support across Dáil Éireann in coming to the recognition that this must be the next step pursued by the Irish Government.
“I am doing this in order to maintain the balance of allegiance and aspiration at the heart of all our political agreements – a balance and a consent my party fought so hard to achieve.
“Northern nationalism cannot be left powerless in the face of Tory/DUP Direct Rule.
“All of democratic Ireland had a role in building and supporting the historic solution we all voted for on this island some 20 years ago.
“The Irish people retain ownership of that solution – it is now more important than ever that all of us stand by them and stand by that solution,” added Mr Eastwood.