Democratic Unionist Party leader Peter Robinson said tonight his party was not ready to agree a deal which would save the North’s power-sharing government.
There had been hope that an agreement on policing, justice and parades would be sealed today.
Earlier, Sinn Féin said it believed a deal was in reach but after at least four hours of internal discussions the DUP leader said his party needed more time.
Mr Robinson said after leaving a meeting of his assembly group: “The group has identified, because the negotiations have not been completed, some issues that have to be resolved and items about which they need to be satisfied.”
It is the latest delay in talks which have been running for more than a week at Hillsborough Castle, Co Down, aimed at resolving an impasse on the devolution of policing and justice powers from Westminster to Stormont.
Mr Robinson indicated his party wanted to see the devolved political institutions continue.
He said he would meet representatives from the Irish and British governments later tonight, as well as members of the other political parties.
“The process is one that we have committed ourselves to as a political party,” he said.
Taoiseach Brian Cowen and British Prime Minister Gordon Brown had been prepared to fly to Belfast to show their support should a deal be reached.