The Supreme Court will hear the plea of two Italian Marines facing trial for murder on Monday.
The marines are expected to ask the apex court to dismiss the charge against them.
Italian diplomat Staffan De Mistura was quoted by the media as saying over the weekend that he did not expect an immediate decision from the Supreme Court, but said that the court would need to indicate when it will rule on the request and the case.
Italian Marine riflemen Salvatore Girone and Massimiliano Latorre, have been detained in India for nearly two years for killing two Keralite fishermen off the coast in February 2012.
Italy intends to ask India to send the pair home, pending formal charges and a trial. The Italian government also wants assurances from India that it will keep an earlier promise that Girone and Latorre will not face the death penalty if found guilty.
Rome has said that it will continue to explore all legal avenues, domestic and global, to get their marines freed.
The two marines claimed that they thought the two unarmed fishermen were pirates and only fired warning shots in the air.
Italy disputes India's jurisdiction over the case, claiming the incident took place in international waters.
The case has sparked off a major diplomatic row between the two countries.
