The winning tenders for a tunnel between Argentina and Chile are to be announced shortly.
Crossing the Agua Negra Pass, the tunnel will be built along the central area of the border between the two countries and will cut current travelling time by three hours and make it easier to for the countries to trade.
The scheme consists of two 13.9km tunnels, approximately 4,800m above sea level in Argentina, and 3,600m on the Chilean side, along the longest border in South America through the Andes mountain range.
Predicted to cost $1.5bn (£1.1bn), 23 companies from across the world, grouped into ten consortiums, have expressed an interest in building the tunnel, which will take ten years to complete.
Currently Argentina and Chile have 26 border crossings, but most are not suitable for freight traffic and are closed for long stretches of the year because of weather conditions.
The Agua Negra Tunnel Binational Entity (Ebitan), created by the two governments, will announce which consortiums will go further in the tender process shortly.
When completed 72% of the road and tunnel will belong to Argentina, with the remaining 28% belonging to Chile.