Moamer Gathafi's last prime minister became the highest ranking former regime official to go before Libyan judges, in a brief but sullen court appearance on Monday.

Dressed in a traditional white robe and brown vest, Al-Baghdadi al-Mahmudi sat in stoney silence within a caged section of the Tripoli criminal court, where figures of the toppled Gathafi regime are facing justice.

The judge did not read out the charges but Taha Baara, the spokesman for the prosecutor general, said Mahmudi "is accused of committing prejudicial acts against the security of the state and financial crimes".

Two other defendants being tried along with Mahmudi were not brought to court, triggering protests from the defence team, which also requested more time to study the case.

"It is a big file. I need more time in order to get myself ready for the defence," lawyer Ali Dabba said.

The session lasted about 10 minutes before the trial was adjourned until December 10 at the request of both the defence and the prosecution.

Mahmudi fled to neighbouring Tunisia in September last year shortly after rebels seized Tripoli and effectively put an end to more than four decades of iron-fisted Gathafi rule.

He was extradited to Libya to face justice on June 24, despite warnings from rights groups that he could face the death penalty.

In July, Mahmudi protested his innocence to journalists visiting his prison.

"I am not guilty, not guilty, not guilty," he told reporters during a visit organised by the authorities in an apparent bid to quash rumours he had been tortured.

"I am ready to be tried by the Libyan people. I am sure of myself and of my innocence," he said at the time.

Mahmudi had appealed his extradition from Tunisia on the grounds he had applied for refugee status and could face execution if sent back to Libya.

Along with Seif al-Islam, the toppled dictator's most high-profile son, Mahmudi is one of the few remaining keepers of the many state secrets under Gathafi, who was killed on October 20 last year.

A physician by training, Mahmudi was loyal to Gathafi until the end, serving as premier from 2006 up to the final days of his regime.

From March 5, 2006 through the war of 2011, Mahmudi was the secretary of the General People's Committee, the equivalent of the country's prime minister.

He held a series of government posts before that, including health minister from 1992 to 1997, as well as shorter stints as minister of human resources and minister of infrastructure.

Mahmudi oversaw vast fortunes in the oil-rich nation as chairman of the Libya Investment Authority, one of the largest sovereign wealth funds in the world which was created in 2007 to restructure state enterprises.

He also oversaw the Libyan Oil and Gas Council which was created in 2006.

Gathafi's son Seif al-Islam, arrested inside Libya a year ago, is awaiting to hear where he will stand trial for alleged crimes against humanity.

The authorities in Tripoli want him to stand in the dock inside Libya, but the International Criminal Court wants him to face justice in The Hague.

Judges in The Hague heard arguments last month by a lawyer for Libya and representatives of the ICC to decide where Seif, 40, and Gathafi's former spymaster Abdullah Senussi, 63, should be tried.

Seif has been in custody in the western Libyan hill town of Zintan since his arrest last November, while Senussi was extradited from Mauritania on September 5.