The announcement comes as the deadlock over arms decommissioning continues to delay implementation of the Good Friday agreement.

Ireland Correspondent Mark Devenport: "Still quite a gap between unionists and republicans"

Mr Ahern will be accompanied at Stormont on Monday by Irish Foreign Minister David Andrews and his deputy Liz O'Donnell.

But by the time the talks take place, the 31 October target date set for forming a shadow executive in the new assembly will have passed.

Round-table talks in the afternoon are scheduled to be followed by bilateral exchanges with the parties.

Mr Ahern has had already held a series of meetings in Dublin with political chiefs from both sides of the Ulster border to assess developments affecting the peace accord.

David Trimble: IRA must hand over weapons

Talks between Mr Trimble and the Sinn Fein leader Gerry Adams on Friday failed to find any way through the impasse.

Ulster Unionists described the talks as the worst of the four meetings that have taken place between the two men.

Rival parties were due to have agreed on the composition of a ministerial executive and on the scope of new bodies to forge closer links between the British-ruled province and the Irish republic to the south by the end of October.

Gerry Adams maintains his party, Sinn Fein, should have seats

Deputy First Minister Seamus Mallon told the Northern Ireland Assembly on Monday: "I feel a deep sense of frustration and I believe that frustration is shared by all members of this assembly,especially because people realise the enormous opportunity and potential that exists at this present time."

Mr Trimble says members of Sinn Fein cannot take their seats on the new executive, which will administer vast swathes of daily life in Northern Ireland, until the IRA has started to hand over its weapons.

But Sinn Fein says the Good Friday Agreement sets no such condition for joining the executive.