The IRA has agreed to allow a Protestant and a Catholic churchman to witness any future decommissioning of its weapons, the BBC has learned.
Decommissioning of weapons has been the key stumbling block
It is expected that the IRA offer will be detailed in government papers to be handed separately to Sinn Fein president Gerry Adams and DUP leader Ian Paisley during meetings in Dublin and London on Wednesday.
Making the IRA's acts of "putting weapons beyond use" more visible has been one of the major sticking points in the negotiations to restore a power-sharing government in Northern Ireland.
According to the BBC Northern Ireland's Spotlight programme, sources say agreement on having churchmen as witnesses was reached during negotiations held since the Leeds Castle talks in September.
The Democratic Unionists and Sinn Fein have been involved in intensive - though indirect - talks as the main unionist and republican parties in Northern Ireland.
As an incentive to help bring about an agreement, the IRA has offered major acts of decommissioning, but the DUP's negotiators want more evidence than the word of General John de Chastelain, the head of the independent arms decommissioning body.
The offer of allowing other witnesses to see it is a significant move by republicans - but it is still not clear whether it will be enough for the DUP.
However, it would only happen in the event of a comprehensive deal being reached on a new devolved government at Stormont.
Reporting for Spotlight, the BBC's Northern Ireland security editor Brian Rowan said there was no agreement yet who the two churchmen would be.
He added: "So far, none of this had been discussed in direct talks between the IRA and General de Chastelain.
"Inside the negotiations, efforts are still being made by the DUP to secure photographic evidence of decommissioning."
Brian Rowan said the British and Irish Governments want to discuss whether photographs could be taken and if so, could they be published or shown privately to those who need to be convinced? Up to this point, republicans have said: "No".
In recent weeks, the DUP has said progress has been made since the Leeds Castle talks and the agreement on church witnesses seems to confirm this.
The Chief Constable, Hugh Orde told Spotlight the "visibility issue" surrounding decommissioning was a difficult one to square.
"It seems to me there is going to have to be something more than just General de Chastelain making a statement.
"I think there's going to have to be something more visible if people, if communities, are going to be convinced that this is a very real event."
Speaking about who might be chosen as witnesses, the Moderator of the Presbyterian Church, Ken Newell, told the programme: "These have to be people who are trusted.
"These must be people whose word is their bond - people who are against any kind of exaggeration or hype because people today have a great scepticism against the whole spinning industry.
"They want people to speak the truth - to tell it as it is and talk straight."
A DUP spokesman declined to comment on the Spotlight report, saying it was a matter for negotiations.
Sinn Fein President Gerry Adams said: "Every negotiation, particularly as it comes to a crucial point is rife with rumour and speculation.
"None of the issues involved in the current effort to find a breakthrough have been agreed or closed on."
SDLP leader Mark Durkan said: "The approach of using clergy as witnesses has been mooted before and may take us forward now but the reality is that previous acts of IRA decommissioning
haven't been done in a way that maximise confidence."
The power-sharing devolved institutions in Northern Ireland were suspended two years ago amid allegations of IRA intelligence gathering at the Northern Ireland Office.
Spotlight is transmitted on BBC One Northern Ireland at 2225 GMT on Tuesday.