Libyan authorities have met resistance in talks for the handover of Saif al Islam, the son of slain leader Muammar Gaddafi, who is still being held in Zintan, a negotiator told AFP on Tuesday.

Zintan officials told representatives of the ruling National Transitional Council that people in the town "want Saif to be tried locally because the (interim) government is weak," an NTC member said on condition of anonymity.

They consider the "interim government incapable of conducting a secure trial for Saif al Islam" and unable to prevent him from fleeing Libya in the same way that other members of the regime have, he added.

The NTC member was part of a delegation that went to Zintan, 180 kilometres (110 miles) southwest of Tripoli, on Monday to meet with city officials and former rebels who are holding Saif in an undisclosed location.

Interim leader Mustafa Abdel Jalil attended a second round of talks on the issue held in Tripoli on Tuesday, according to the same source.

Abdel Jalil stressed that "it is necessary for Saif al Islam to be transferred to Tripoli" in order to "relieve the pressure" exercised by the International Criminal Court on the Libyan authorities, he continued.

The NTC also highlighted that it would be "difficult" for the international community to accept a "trial controlled by revolutionaries," or former rebels who fought against Gaddafi's forces in 2011.

Zintan officials requested "time to think about it and consult with residents before answering," the same source added.

Libya's representative to the ICC, Ahmed al-Jehani, had announced on April 7 that Saif would be transferred to Tripoli "before the end of the week," but that deadline has passed.

Saif, who was arrested on November 19 in southern Libya, is being held in a secret detention centre in Zintan, where he has allegedly been mistreated by his wardens.

The ICC wants to bring Saif to The Hague to face charges of crimes against humanity for his role in battling the uprising against his father last year, but Libya's new government wants to try him at home.