Tony Blair will hold a series of meetings in Belfast before making an historic address to the two Houses of the Irish Parliament in Dublin on Thursday.

Meanwhile, the main political parties are aiming to agree on key structures of the new Stormont Assembly.

Tony Blair: Major hurdles

Mr Blair faces major hurdles in overcoming the stumbling block of disarmament, which has delayed the establishment of a power-sharing executive in the new administration.

But the province's politicians have indicated that a deal could be within reach on areas of cross-border co-operation and the number of ministerial departments to be created at Stormont.

They hope the agreement will be ready in time for the planned transfer of legislative powers from London to Belfast next February.

First Minister David Trimble and his deputy Seamus Mallon are looking for agreement on North-South bodies and the British-Irish Council by the end of the month.

Blair pressed on arms promise

Mr Mallon said: "I would hope that by the end of this week, or possibly next, things would be much clearer."

The parties are still divided on the number of Stormont departments. Apart from the Unionists, most are pushing for 10.

At the same time, the gap appears to be closing on the type of north-south arrangements to be introduced under the terms of the Good Friday Agreement.

But there have been no signs of movement by the IRA and loyalist paramilitaries to begin getting rid of their weapons and explosives.

Mr Trimble will tell Mr Blair about heightening anxieties inside his own party when they meet on Wednesday.

The Unionist leadership is looking for him to stand by a written assurance on disarmament, which effectively said republican representatives would be excluded from holding office at Stormont if the decommissioning provisions in the agreement had been "shown to be ineffective" after six months.