The Irish and British governments will publish their plan to break the impasse over the North's suspended powersharing institutions in three weeks time.
President Bush has pledged to support their efforts later this year, the Taoiseach said yesterday.
Speaking after meeting President Bush in the White House yesterday, Mr Ahern said there was unanimous political backing in the United States for the governments' approach.
"There is a unanimous sense from Irish-America, friends in the Senate and [ Capitol] Hill - the president shares it, Prime Minister Blair shares it - that we just have to move on," Mr Ahern said.
President Bush hosted a reception in the White House for about 100 people yesterday after his talks with the Taoiseach. While the leaders of the main parties in the North - except the DUP who chose not to attend - were present, Mr Bush did not have a substantive discussion with any of them.
He had a short private discussion earlier with the families of Robert McCartney and Joseph Rafferty, and the Taoiseach said he was "extremely well briefed" on these cases.
The announcement that an initiative would be taken by the two governments next month follows the deferral of plans to publish joint plans a few weeks ago.
This followed vehement Sinn Féin and SDLP opposition to the idea of setting up a "shadow assembly" in advance of restoring the powersharing executive - a move favoured by the DUP.
The Minister for Foreign Affairs, Dermot Ahern, told The Irish Times yesterday that the Government had never been enthusiastic about this idea.
The Taoiseach gave no detail of what was planned, but insisted it was a path towards restoring all of the institutions: "That's the Assembly, that's the Executive, that's North/South bodies, that's east/west ministerial councils," he said. "That's the way we want it to work. It is only if that fails we will move to Plan B."
Asked about "Plan B", the Taoiseach said this had not been decided upon, but the two governments had given some thought to it. "It would be unwise not to do that," he said.
Dermot Ahern said any "Plan B" would involve much more inter-governmental co-operation on the running of Northern Ireland.
He said many people in the business communities North and South were demanding greater cross-Border co-operation, and the two governments would act upon this if there were no deal between the parties this year.
Over the past two days, Democratic and Republican congressmen called on Sinn Féin to sign up to the new policing structures in the North, but made it clear that they saw the DUP's refusal to engage with Sinn Féin as the primary obstacle to progress. This view was echoed by Dermot Ahern, who said yesterday that in relation to the process, "the elephant in the corner is the unionist community. The question is are they prepared, as they said they would, to share power with nationalists, and we will be asking them that question over the next couple of months."
The Taoiseach insisted that all obstacles raised by unionists had been or are being dealt with.
"We have seen the end of the IRA campaign, we have seen the end of the arms issue, we are dealing with the criminality issue, you saw the big raids at the Border last week. The politicians have to get back to the work they were elected to and they have to do it this year."
He said President Bush had said that later on this year, when efforts would be made to get all the parties to agree to restore the power-sharing institutions, he would give any support that was required.
Dermot Ahern said the Government "won't be budging" from the position that all of the institutions had to be restored in any deal.
However, it is not clear whether the plan will suggest the restoration of these institutions simultaneously, or in sequence.