Uruguayan courts Wednesday received the cases for the third mass transport of political prisoners to Uruguay from Argentina in 1978.
The shipping of prisoners was part of Plan Condor, a 1970s operation in which the military governments of Argentina, Bolivia, Brazil, Chile, Uruguay and Paraguay worked together to eliminate opposition figures.
Oscar Lopez Goldaracena, a lawyer for the Peace and Justice Service asked the Montevideo tribunal to investigate the disappearance of 40 opposition politicians.
Uruguayan judge Luis Charles is already investigating a 1976 Uruguayan Air Force flight which brought more than 20 opposition figures to Uruguay where they were later killed. It is known as the Second Death Flight.
Lopez said that members of left-wing groups were kidnapped in Buenos Aires in 1977, jailed for several months and then transferred to Uruguay where they were executed.
The court case names navy captain Jorge Troccoli and former dictator Gregorio Alvarez, but also implicates all those from the army, the air force and the navy.
The case calls for the excavation of military files and the land at La Tablada, a jail close to Montevideo, seeking the remains of opposition figures.
Uruguay's dictatorship is said to have been responsible for the disappearance of 200 people, including more than 100 from Plan Condo.
The government of President Tabare Vazquez began investigating the disappearances in March 2005 and has identified the bodies of two opposition politicians buried on military land.