The National Roads Authority hopes to open the Castletown to Nenagh section of the M7, which links Dublin with Limerick and Kerry, on Wednesday.
The opening of the 36km section of road was being held up because of a dispute over payments.
The dispute was between the NRA, Laois County Council, main contractor Bowen Somague Joint Venture, and subcontractors KC Civil Engineering and Cappawhite Plant Hire.
Over 40 workers from the two subcontracting companies had picketed and blocked a number of sites on the road last week, because they had not received payments since 1 November.
The workers also picketed at the offices of the NRA and at the Dáil last week.
They had also written to Taoiseach Brian Cowen to ask him to intervene in the dispute, as a large section of the new motorway is located in his constituency.
Bowen Somague has said that constructive discussions had taken place between the parties to try and reach a settlement in recent days.
The NRA confirmed this morning that there had been a breakthrough in discussions, which would allow the road to be opened on Wednesday.
The workers who had been in dispute were working on the site over the weekend. It is expected that the road will be open to motorists in time for the big travel exodus to Limerick and Kerry regions in time for Christmas.
It is the very last section of the State's €18bn intercity motorway programme linking Dublin with all the major cities to be open.
