The African Union and Amnesty International have raised concerns about the treatment of prisoners saying there is potential for abuse of the detainees, many of whom insist they are migrant workers.
Tripoli's new ruling council believe there could be more than 5,000 people who have been detained in the capital amid fears they were mercenaries fighting on behalf of Colonel Muammar Gaddafi.
The National Transitional Council has demanded fighters refrain from abusing prisoners and insisted those accused of crimes will receive a fair trial.
Justice minister Mohammed al Alagi said he had visited several places where detainees were being held and told reporters they were "up to international standards".
But reporters in the capital have described seeing around 200 detainees held at a sports club, where the lack of a roof meant prisoners were forced to gather by a high wall to seek shade.
Those running the detention centre admitted they had little experience in dealing with prisoners and medical facilities were still being established.
"The danger is that there is no oversight by any authorities, and the people who are carrying out the arrests, more like abductions, are not trained to respect human rights," Amnesty International's Diana Eltahawy said.
"They are people who carry a lot of anger against people they believe committed atrocities."
At the start of the conflict, there were reports of African mercenaries being flown in by Col Gaddafi to try stop the rebellion.
It led many to suspect those with sub-Saharan African heritage were involved in defending the collapsed regime.
Around 800 migrant workers have taken refuge in a camp, afraid to try to return home in case they are arrested by anti-Gaddafi forces.
Post published in: World News