Libya said earlier this month that it would complete within weeks its investigation into Saif al-Islam and asked the International Criminal Court to once again to hold off ordering his surrender.
Pressure is mounting on Tripoli to hand Saif al-Islam to the ICC - which indicted Saif al-Islam in June for crimes against humanity - as human rights groups question whether its justice system can meet the standards of international law.
Libyan Deputy U.N. Ambassador Ibrahim Dabbashi told the U.N. Security Council on Wednesday that Libyan law prevented Saif al-Islam Gaddafi from standing trial without a lawyer.
"This matter has mainly got to do with Saif al-Islam Gaddafi, who until now refuses appointing an attorney to defend him. Hence the matter is not in the hands of the Libyan authorities but rather the defendant himself, but there are no obstacles towards hiring an attorney to defend him," he said.
Libya's government and the war crimes court have argued for months over where he should be tried.
Libya will eventually have to outline to the ICC how it intends to try Saif al-Islam. If the court concludes that Libya cannot or will not try him, and is not cooperating with the ICC case, it can refer Tripoli to the U.N. Security Council.
"I would like to assure the council and everyone that Saif al-Islam Gaddafi will have an attorney because Libyan law does not permit the trying of any defendant in criminal cases unless with the presence of a defense attorney," Dabbashi said.
Last month a senior defense lawyer at the ICC said Saif al-Islam had been physically attacked and was suffering dental pain. Libya has denied this.