The Argentine prosecutor who accused President Cristina Fernandez de Kirchner of whitewashing the investigation of Iran over the 1994 bombing of a Jewish community centre has been found dead in his Buenos Aires apartment, according to authorities.

The body of Alberto Nisman, who was expected to reveal damning allegations involving Fernandez at a closed-door hearing in Congress, was found in a pool of blood in his bathroom in the luxurious Buenos Aires district of Puerto Madero.

Appointed 10 years ago by the president's late husband Nestor Kirchner, Nisman accused Fernandez of opening a secret back channel to an Iranian gang who reportedly planted the car bomb that killed 85 people at the AMIA Jewish community centre in the Argentine capital.

He claimed the plot was orchestrated to clear the suspects to import oil and export grain to Iran.

"Dr Nisman has died, we are investigating the cause of the death. In the coming days we will determine the cause of death with an autopsy. We found a weapon," prosecutor Viviana Fein told journalists.

"I ask for seriousness, I ask for prudence."

Fernandez formed a "truth commission" in 2013 with Iran to jointly investigate the 1994 bombing. Israel and Jewish groups said the move threatened to derail criminal prosecution of the case.