A planned meeting between delegations from the DUP and Sinn Féin at Stormont was postponed this afternoon.
The Taoiseach told ministers he was disappointed at the latest setback, but he urged people not to walk away from the deal on offer.
Mr Ahern said that policing was just one of many outstanding issues, and the timeframe built into the St Andrews agreeement was designed to allow people work through problems.
It is likely Mr Ahern will speak to Tony Blair on Friday on the fringes of a European Summit in Finland.
The Stormont meeting was expected to address the new programme for government in Northern Ireland which was produced at St Andrews in Scotland last week.
This afternoon, a senior DUP source said the meeting was postponed and that the party would not allow the Northern Ireland Office and Sinn Féin to unpick what the source described as 'the prior delivery on policing'.
The DUP has said a pledge on policing must be taken by the proposed First Minister and Deputy First Minister on 24 November.
This morning, DUP MEP Jim Allister said he had grave difficulties with the proposed St Andrews agreement.
Speaking on RTÉ Radio's Morning Ireland, Mr Allister said he objected to the fact that parties would be compelled to share power in all circumstances.
Mr Allister, who is seen as among the most entrenched hardliners within the party, identified the question of an oath in support of the PSNI.
The DUP is adamant any such oath taken by Sinn Féin's Martin McGuinness should be taken on 24 November.
It is unlikely that the Sinn Féin Ard Fheis will have taken place by then, although the Ard Comhairle vote should be known in advance of the November deadline.
Mr Allister said he was looking for improvements in the St Andrews agreement before he could endorse it.
He said he had particular concerns over the absence of an eviction mechanism against single parties and the continuation of mandatory coalition which is built into the agreement.
Referendum may be needed: Ahern
The Minister for Foreign Affairs, Dermot Ahern, has said that a referendum on the St Andrews agreement may be required before power-sharing is restored.
Mr Ahern said that the Government would only decide on whether to proceed with a referendum after consulting with the Attorney General.
The detailed St Andrews plan includes a reference to a possible British government initiative on corporation tax, which might involve offering special tax incentives for Northern Ireland as a region of the UK.
RTÉ News understands that if the British government was to take such an initiative to encourage investment in Northern Ireland, the Government would support it at EU level.
