Northern Ireland First Minister Peter Robinson believes a deal on issues such as paramilitary activity and welfare reform must be done at Stormont in the next 10 days or "there will be no agreement".

The five main parties — the DUP, the UUP, Sinn Féin, the SDLP and Alliance — have been in negotiations for nearly six weeks on topics which also include the legacy of the conflict in the North.

“We are coming to the vital stage, the endgame,” Mr Robinson said on Thursday. “It is my view that if we cannot reach agreement, then the process itself will be terminated.”

Mr Robinson resumed his position last week after temporarily stepping aside while an independent report on the status of paramilitary groups was prepared in the aftermath of the August murder of republican Kevin McGuigan, which police linked to the IRA.

He spoke of there being a “very significant responsibility on all those who are in leadership in Northern Ireland”.

In comments thought to be directed at unionist rivals, the DUP leader, suggested there are “the whingers, the wreckers, the political snipers who hope for failure”.

“There are people quite clearly who think they will have some advantage if the process breaks down,” he said.

“To use a recently quoted phrase, ‘they are on the wrong side of history if they think it is advantageous to bring this process down’.”

UUP leader Mike Nesbitt has said his party will remain in the talks but will not support "handing out the begging bowl to London again".

He claimed his party was being attacked by Sinn Féin and the DUP in recent days and this was an indication the UUP is “irritating the two big parties who are clearly busting to do a side deal at Stormont Castle”.

On Wednesday, Deputy First Minister Martin McGuinness suggested a deal was achievable in “days, not weeks” but on Thursday his Sinn Fein colleague Gerry Kelly MLA said he was concerned about the British government’s approach to dealing with the legacy of the past.

Mr Kelly accused the British government of trying to minimise the role of the state in the conflict and that this was unacceptable to his party and victims’ groups.

“All measures to deal with the past, including any legislation, must reflect the commitments made at Stormont House by the parties and the two governments,” he added.

Northern Secretary Theresa Villiers has warned there is "very limited time left" but added that she was encouraged by the parties continuing intensive engagement on a range of difficult issues.

“It is essential a successful conclusion is reached very soon,” she said.

“Next week could be crucial to the success or failure of this process.

“The Stormont House Agreement has to be implemented in full and we need measures to address paramilitary activity if we are to make progress in building a brighter more secure future for Northern Ireland.”