The Taoiseach yesterday hailed the establishment of the final two institutions of the Belfast Agreement and called on paramilitary organisations to take steps to end the controversy over decommissioning.
Saying that armed organisations should help the political process by "decommissioning decommissioning" as an issue, he said he looked forward to the new political institutions operating fully in the new year.
The establishment yesterday of the British-Irish Council and British-Irish Intergovernmental Conference completes the most intensive three-week period of political development since the peace process began.
Irish and British government sources continue to hope that the rapid political development will ensure that the decommissioning issue does not collapse the new institutions when it arises again at the Ulster Unionist Council in just over two months.
Welcoming the successful establishment of all the institutions, Mr Ahern told a press conference in Downing Street that he looked forward "at the other side of the millennium to making them operate and using our energies to make them successful."
He pointed to the attendance of the North's new Agriculture Minister, Ms Brid Rodgers, at the EU Fisheries Council this week with the Irish Minister for the Marine, Dr Woods.
They had argued a common case in the interests of the population, North and South, and the fisheries issue had also been discussed collectively yesterday.
The Government has undertaken to prepare a paper on how the participants in the British-Irish Council can co-operate to tackle illegal drug-trafficking and abuse. That paper will be discussed at the next plenary session of the council, in Dublin in June next year.
Mr Ahern said 20 items had been agreed for discussion, "and it could have been 120".
Responding to questions, he said the issue of Sellafield was among the 20 items and could be discussed by the British-Irish Council in the future.
While warmly welcoming the establishment of the British-Irish Council, Mr Ahern again stressed: "We are linked in an especially close partnership with the new Northern Ireland Executive in the North-South Ministerial Council, which we launched earlier this week in Armagh and which we inevitably see as especially significant".
His comment reflects the fact that his Government sees the North-South Council as of paramount importance, establishing all-island institutions for the first time. Unionists, however, see the British-Irish Council as of particular importance, as its existence suggests the resolution of the conflict on the island lies in a broader British-Irish context rather than simply a North-South one.
Meanwhile, the devolution of powers to the new institutions in the North means the new British-Irish Intergovernmental Conference will be weaker than its predecessor, the Anglo-Irish Intergovernmental Conference, established by the 1985 Hillsborough Agreement.
Yesterday's joint communique notes "the Irish Government's special interest in Northern Ireland". However, the new intergovernmental conference will only discuss policy areas which have not been devolved to the new Northern Ireland institutions, such as policing, justice and broadcasting.
However, Dublin Government sources point out that while many issues have been removed from the ambit of the Intergovernmental Conference, they will now be discussed directly between Ministers, North and South, through the North-South Ministerial Council.
Northern Ireland politicians will attend meetings of the new Intergovernmental Conference.
The First Minister, Mr David Trimble, and Deputy First Minister, Mr Seamus Mallon, were at yesterday's Downing Street meeting.