An AFP correspondent attending the proceedings said the first session of the trial was held under tight security.
The 15-lawyer defence team for the accused contested the proceedings, saying most of the accused are civilians but are being prosecuted in a military court.
The trial was later adjourned to February 15.
The New-York based Human Rights Watch (HRW), in its World Report 2012, has raised concerns over Libya’s judicial system.
“Libya’s interim government and its international supporters should make it an urgent priority to build a functioning justice system and begin legal reform that protects human rights after Muammar Gaddafi,” the group said in the report.
HRW and two other human rights groups, Amnesty International and Doctors Without Borders, have also accused former rebels who helped topple Gaddafi’s 42-year-old rule of “torturing” their prisoners, mainly ex-regime loyalists.
On Friday, HRW noted that a former ambassador to France, Omar Brebesh, died of possible “torture” in the custody of a militia less than 24 hours after his detention in Tripoli.
Amnesty International and Doctors without Borders have also charged that the militias use “widespread torture” against their prisoners in cities such as Tripoli, Misrata and smaller towns like Ghariyan.
Doctors Without Borders even suspended its work in Misrata over allegations of torture in prisons there.
Libyan officials insist that the country’s judiciary is “competent” to handle the legal cases of former regime members, including putting on trial Gaddafi’s most prominent son, Seif al-Islam.
Seif, 39, who was arrested on November 19, is in the custody of the military council of Zintan, a town 180 kilometres, southwest of Tripoli.
He is wanted by the International Criminal Court on charges of crimes against humanity allegedly committed during the conflict.