Naji al-Issawi, a commander in a unit of Tripoli’s military council, showed reporters two corpses exhumed from a cemetery which he said contained between 200 and 300 corpses.
Issawi said officials planned to dig up more of the site in the Gargarish district and start identifying the remains.
An official from the cemetery said the corpses had been collected from streets and hospitals following the rebel assault on the Libyan capital in late August.
One of the corpses displayed on Wednesday was largely decomposed and appeared to be clad in military fatigues and boots.
Issawi said a separate burial site elsewhere in the capital had been discovered and could contain as many as 700 bodies.
Since Gaddafi was toppled, more than a dozen sites have been identified as mass graves, including one at the capital’s Abu Salim prison, site of a 1996 massacre of about 1,200 people that became a rallying point against Gaddafi in the early days of the Libyan uprising.
There have been conflicting reports of how those burial sites came into being. Even members of the country’s ruling National Transitional Council (NTC) have disagreed.
New York-based Human Rights Watch has urged the NTC to halt excavations of such sites, warning that exhuming remains without proper forensic techniques could make it impossible to identify people buried in them.