Foyle MP Colum Eastwood has said joint rule between Dublin and London will be the outcome if the parties in the North and the two governments fail to reach a deal to get Stormont back up and running.
"There is nothing called direct rule any more. That is gone. It is outlawed. We cannot go back to the days of rule from this place over the people of Northern Ireland," he told MPs at Westminster on Wednesday night.
"The Good Friday agreement, the St. Andrews agreement, and every agreement since states that devolution is how we do our business now."
The SDLP leader said the resurrection of the power-sharing institutions was the only outcome his party wished to see.
However, he warned that nationalists in the North would not tolerate direct rule.
"If we cannot have devolution - although we should not countenance that - people need to understand that the automatic response is not direct rule, because the nationalist population will not accept it, the Irish Government will not accept it, and the St. Andrews agreement has ruled it out as an option.
"So what must we do? We must recognise that a voice in governance must be given to both sides of our community, to all the minorities; and we are all minorities in Northern Ireland now.
"If we do not compromise, the next step will be not rule from London, but some form of joint rule from London and Dublin. People need to recognise that when we are talking tough in these negotiations," he declared.
Mr. Eastwood said compromise was long overdue.
"It is time to bury the hatchet, because the issues that are at stake in these negotiations, important though they are - and I have strong views on all of them - are not as important as people dying on waiting lists, they are not as important as nurses not being paid properly, and they are not as important as our schools not being able to fund the education services that we need to give to our young people," he stated.