A motorway between Limerick and Cork could generate up to €128m for the local economy, according to a report commissioned by Cork and Limerick Chambers.
The report for Cork and Limerick Chambers, titled 'Gearing up for the M20: A Route to Success', shows the proposed 80 kilometre M20 has the potential to create up to 5,400 direct jobs.
It also found that the scheme would prevent around 118 accidents a year and would reduce stress and improve the quality of life for commuters.
The Chambers say that the development would see a continuous motorway from Cork all the way to Galway via Limerick, "creating an economic corridor that would provide a strong complement to Dublin".
The report also suggests that the motorway would increase the labour force within a 45-minute commute of major employment centres by 23%.
Dr James Ring, CEO of Limerick Chamber, said: "The M20 is probably the most significant piece of infrastructure yet to be developed in the State.
"It would effectively create a three-city region with a critical mass at a level that would redouble its capacity to win major inward investment. Two of those cities, Limerick and Galway, will have motorway/dual-carriageway connectivity by the end of this year.
"The M20 to Cork is the missing link and its delivery would be of national significance in that it would finalise that three-city corridor, benefitting not just the South West, Mid-West and West but with the ripple effect extending out into the North West, Midlands and South East."
Conor Healy, CEO of Cork Chamber, added: "The need for a motorway connection between Cork and Limerick can no longer be ignored or postponed. It is in the national interest that our regional economies expand for Ireland to remain competitive and to complement growth in Dublin.
"With the right road network linking them, Cork, Limerick and Galway could effectively become one large labour and customer marketplace improving opportunities and choice for employees and businesses, while also enhancing safety for all users of the road."