Anti-war campaigners have rejected claims by the Taoiseach, Mr Ahern, that international law did not regard the provision of landing and overflight facilities to the US military as support for the war against Iraq.
The chairman of the Peace and Neutrality Alliance, Mr Roger Cole, said such assertions were "completely and utterly untrue" and in conflict with the findings of a recent High Court judgment.
Mr Ahern insisted again yesterday that he was opposed to the war. He rejected suggestions that his position was ambiguous and said he had always been consistent. Asked whether the war was justified, he said the "issue will go on for a long time".
He said that France and Germany, which were regarded as opposing the war, had "allowed overflights and movement of huge military equipment on the ground".
"We wanted to see a new UN resolution before any action took place. We didn't see that, so therefore we were opposed to the war when the war started. The question was then how do you then deal with the issue of overflights," said Mr Ahern.
"Under international law, allowing overflights in that situation was not a pro-war stance and that is recognised everywhere except by a handful of people in this country."
Mr Cole drew attention to the High Court judgment last April in a case taken against the Government decision by a former Army officer, Mr Edward Horgan.
Mr Justice Kearns dismissed the challenge, stating that Mr Horgan was effectively asking the court to tell the Dáil to resolve afresh on a matter on which it had already resolved.
Without proof that the circumstances were "quite exceptional", he could not accept the implied contention that the court was better suited than the Dáil for deciding what constitutes "participation" in a war.
However, the judge said there was an identifiable rule of customary law in relation to the status of neutrality "whereunder a neutral state may not permit the movement of large numbers of troops or munitions of one belligerent State through its territory en route to a theatre of war with another".
While the policy of neutrality was not enshrined in the Constitution or in domestic legislation, the judge said legal concepts of neutrality existed in international law in which "co-relative rights and duties arise for both belligerents and neutrals" in wars that were not UN-led.
Mr Justice Kearns referred to the Hague Convention V of 1907, which forbids neutral states from allowing states engaged in war to move troops, supplies or munitions across their territory. The convention had not been ratified in Irish law, but he said the texts used by Mr Hogan tended to support the view that it reflected "customary international law".
He acknowledged that the State had argued that "a more qualified or nuanced form of neutrality also exists", such as the one practised by this State for many years.
Mr Justice Kearns added: "It does not appear to me that even that form of neutrality is to be seen as including the notion that the granting of passage over its territory by a neutral state for large numbers of troops and munitions from one belligerent State only en route to a theatre of war with another is compatible with the status of neutrality in international law.
"No authority has been offered to the court by the defendants to support such a view, nor can it be an answer to say that a small number of other states have done the same thing in recent times."
The judge said it was necessary to consider how international law interacted with Irish law. The rule of international law must in every case yield to domestic law where a conflict arose.