By Marie-Louise Gumuchian

TRIPOLI (Reuters) - Muammar Gaddafi's former intelligence chief, jailed in Libya for eight months, has not seen a lawyer or been told what charges he faces, Human Rights Watch said on Wednesday, underscoring concerns about weak rule of law under transitional rule.

Abdullah al-Senussi, once among the most feared members of the Gaddafi regime, is wanted by the International Criminal Court (ICC). But Libyan authorities who evolved out of the rebel movement that overthrew Gaddafi in 2011 are resisting an order to hand him over, saying their courts are capable of trying him.

"Libya's wish to put the people they hold responsible for gross human rights violations on trial is fully understandable," Sarah Leah Whitson, Middle East and North Africa director at Human Rights Watch (HRW), said after the first visit by an international rights group to Senussi's jail cell.

"But to achieve true justice, they need to give Senussi the rights that the previous government denied Libyans for so long. To start, that means making sure he can consult a lawyer," Whitson said in a statement.

HRW interviewed Senussi in the al-Hadhba Corrections Facility in Tripoli, a newly renovated center holding several senior Gaddafi-era officials.

Senussi did not complain of physical abuse and said his conditions in custody had been "reasonable", the statement said. His main grievance, it said, was lack of access to a lawyer. HRW quoted him as saying he had asked for one on the second or third day after arriving, but to no avail so far.

HRW quoted Justice Minister Salah al-Marghani as having said: "Senussi has the right to a defense lawyer of his choice like any other person standing trial ... Libya is committed to provide a fair trial."

Senussi is suspected of playing a central role in the killing of more than 1,200 inmates at Tripoli's Abu Salim prison in 1996. It was the arrest of a lawyer acting for relatives of the victims that sparked the anti-Gaddafi revolt.

He has also been linked to the 1988 bombing over Lockerbie, Scotland of a U.S. passenger plane that killed 270 people.

Libya's transitional rulers, who aim to draw up a democratic constitution this year, are keen to try Gaddafi loyalists at home to show Libyan citizens that those who helped Gaddafi stay in power for 42 years are being punished.

Human rights activists worry that a weak government in Tripoli and flimsy judicial standards mean that legal proceedings will not meet international standards.

Senussi was arrested early last year after arriving with a false Malian passport on a flight to Mauritania from Morocco.

HRW quoted Senussi as saying that Moroccan authorities had arrested him in March 2012 and then detained him for about 12 days before putting him on a plane to Mauritania, which then extradited Senussi to Libya last September.

As well as giving Senussi full access to a lawyer and formally notifying him of the charges he faces, HRW said, Libyan authorities should also allow visits by lawyers authorized to represent Senussi before the ICC.

He is wanted by the ICC on suspicion of orchestrating brutal reprisals during the 2011 armed uprising that led to the fall and death of Gaddafi.

(Editing by Robin Pomeroy)