The "honest brokers" could be drawn from foreign governments, an organisation such as the United Nations, or an ad hoc commission of overseas security experts nominated by both governments.
The proposal - put forward as an option in a new Anglo-Irish working paper - is gathering political momentum. The mechanism by which the terrorist groups should give up their arms has been one of the most difficult to resolve in the whole peace-making process.
But sources stressed that there was no question of foreign peace-keeping troops being deployed in any capacity in Northern Ireland or the Irish Republic.
The working paper, now being studied in Downing Street, was compiled by British and Irish civil servants at the request of John Major and the previous Irish prime minister, Albert Reynolds, at their final summit last year. It sets out several options on the decommissioning of arms.
Last week the Irish Foreign Minister, Dick Spring, floated the prospect of a third country assisting in the destruction of the arms of IRA and Loyalist terrorists. Visiting Washington, Mr Spring also mentioned the possibility of help from a Scandinavian country or from the Conference on Security and Co-operation in Europe.
A British source said last week that Mr Spring's third party option is "one of the things for which ministers will have to decide if there is a role".
The Ulster Unionists have already put forward similar proposals for decommissioning. Ken Maginnis, Ulster Unionist security spokesman, discussed them at a Downing Street meeting on 15 January. He set out detailed plans for the British and Irish governments to appoint a group of acknowledged international military experts, such as Canada's General Lewis Mackenzie, the first commander of UN troops in Sarajevo.
The Unionists accept that the Americans should be given a role but they would like representatives of other neutral countries to be included.
The involvement of foreign military personnel would avoid the need for the Royal Ulster Constabulary to play a role, which the IRA would be unlikely to find acceptable. Overseas experts could also help verify arms finds in the south.
Mr Maginnis said yesterday that his party would be happy with a commission "appointed by the two governments but we would frown on the idea of the United Nations or a foreign government, like Sweden. Their presence could represent direct interference in the affairs of the United Kingdom and, for that matter, Ireland."
However any third party faces a highly sensitive task in determining whether or not the terrorist organisations have given up enough weapons and explosives to enter the political process. Ministers have always accepted that it is unrealistic to expect every pistol or piece of Semtex to be destroyed or handed over. But the IRA has made it clear no guns will be handed over in advance of any overall settlement in Northern Ireland.
The Irish government might favour a neutral body talking directly to the IRA to get assurances of future intentions.
The issue has been given added urgency by plans for Gerry Adams, the Sinn Fein president, to pay another visit to the United States. He is believed to want to attend a fund-raising dinner in New York next week.
But the US government is concerned about the slow progress on arms and explosives. Under pressure from the British government, it has refused to allow Mr Adams to attend fund-raising events before some agreement is reached on decommissioning.
Unionists pick Gore, page 2Reuse content