Leaders of the 2,500-strong Jewish community in Zagreb say the trial has historical importance for Croatia. Croatian leaders, who declared independence from Yugoslavia in 1991, have been accused of drawing inspiration from the Fascist regime of the Forties.
"Sakic is the last living commander of a concentration camp in Europe. You cannot compare him with Adolf Eichmann [the German Nazi hanged in Jerusalem in 1962 for crimes against the Jewish people], but what that trial meant in Israel, the Sakic trial means for Croatia," Slavko Goldstein, a Jewish community leader, said.
According to the Encyclopaedia of the Holocaust, 600,000 people were killed at Jasenovac, mostly Serbs but also Jews, gypsies and other opponents of the regime. Croatian historians put the figure at around 35,000.
Croatian officials launched a criminal investigation into Sakic, 76, after he gave an interview last April to Argentine television in which he reportedly acknowledged being a commander at Jasenovac. "This is the trial of one man ... but through the trial the truth about Jasenovac, the Holocaust and the genocide against Serbs and gypsies will be re-established," Mr Goldstein said.
Sakic is unlikely to be in court for the opening of the trial as he was taken ill on Tuesday night and taken to hospital.