A $1 billion, 41-km bridge connecting trade partners Argentina and Uruguay is still to be built despite plans for a smaller, $100 million project, a government spokesman said.

The Argentine government met with private investors to take their views on the challenge of bridging the massive Rio de la Plata estuary, which separates Uruguay and Argentina.

Blossoming commercial ties within Mercosur, which also groups Brazil and Paraguay into the world's third largest trade bloc, have made construction of a ground link a high priority for the Argentine and Uruguayan governments.

Officials in Argentina's Buenos Aires province have clamoured for the $1 billion bridge, which would slash 300 km off the 565 km land journey from Buenos Aires to Uruguay's capital Montevideo.

In contrast, the less expensive plan would shave 151 km off the Montevideo corridor - which is also an important gateway to Brazil, Argentina's largest trading partner.

Private investors pitched their plan for the cheaper project to construct a 41 km toll highway consisting of three small bridges near Nueva Palmira, Uruguay, 81 km north of Buenos Aires.