The Taoiseach, Mr Ahern, last night called on the IRA to begin the process of decommissioning "urgently".
Mr Ahern gave a clear signal that such an act was needed now, in a speech to the Fianna Fail parliamentary party in Ennis, Co Clare. It was held after his breakfast meeting with the British Prime Minister, Mr Tony Blair, yesterday.
"I look forward to the scheme for putting weapons beyond use - described at the time as historic - being put back on the table and proceeded with urgently, because that indeed would be historic and no one responding in good faith could gainsay that," Mr Ahern said.
The people of Ireland as a whole wanted to see the agreement succeed and move forward, with the "necessary difficult decisions taken now, not next year, or some time in an ideal but ever receding middle distance".
Referring to the weekend deadline in the North's peace process, Mr Ahern said it was "extremely tight" and they had to be "realistic" as well. Everyone would continue to work to meet the deadline but he indicated that it might be extended.
Urgent action was required by all concerned to safeguard the "inclusive democratic institutions" of the Good Friday agreement, which were one of its most remarkable features.
"That should not be allowed to fail. While tremendous patience has been shown by both governments and by most of the constitutional parties on the arms issue, no one should be in any doubt about the fundamental requirements of democracy, be it in this State under the Constitution, be it in Northern Ireland."
Speaking about the situation in Ardoyne, Mr Ahern described it as a "shameful spectacle of sectarian harassment". He said it showed that many situations could arise in which a police service was vital to protect the rights of the community.
"There should be no obstruction of Catholics who want to join the reformed Police Service of Northern Ireland," he said.
Mr Ahern said it was very appropriate that Fianna Fail was holding its parliamentary party meeting in Co Clare on the 75th anniversary of the foundation of the party. "This is where the founder of our party - and in many respects of our State - Eamon de Valera, won a famous by-election in 1917, a key moment on the road to independence."
He added: "Eamon de Valera was born in New York. For a century or more, this part of Ireland has been the hub of indissoluble links that bind together Ireland and the United States. Indeed, I cannot envisage any situation in the future, in which Shannon would not continue to provide a vital link on a daily basis with the US, and above all New York. We will ensure that this is safeguarded, whatever form our future aviation structures take."