The trial of Muammar Gaddafi's son Saif al-Islam will be delayed by five months to include any relevant testimony obtained via the interrogation of Libya's former spy chief who was arrested last week, the prosecutor general office said on Sunday, Sept 9.

Government officials said in August Saif al-Islam's trial on charges of war crimes - the most high-profile prosecution of a figure from his late father's entourage to date - was due to begin in September.

But the arrest on Wednesday of Abdullah al-Senussi, the former spy chief known as "Gaddafi's black box", has pushed that date back, postponing a trial a lawyer from the International Criminal Court (ICC) has already said is unlikely to be fair.

"We were ready to try Saif al-Islam this month but after bringing back Senussi to Libya, new information will come to light which will delay the trial for at least five months," Milad al-Zintani, lawyer at the prosecutor general's office, told a news conference, according to Reuters.

Senussi was handed over to Libya by Mauritanian authorities after being captured in the West African state in March, triggering a tug of war between Libya, France and the ICC for his extradition.