The defendants are accused of using members of the Faily Kurd community as guinea pigs for chemicals weapons testing and as human shields during Iraq's eight-year war with neighbouring Iran.

"The Iraqi High Tribunal, headed by judge Rauf Rashid Abdel-Rahman, began reading the charges against the 16 accused on Monday," the official said.

Among the defendants are Ali Hassan al-Majid, better known as Chemical Ali, who already faces the death sentence for genocide against the Kurds, as well as Aziz, former interior minister Watban Ibrahim Hassan and Saddam's private secretary Abed Hamud.

The charges relate to a violent campaign against the so-called Faily Kurds, who unlike most Kurds follow the Shiite branch of Islam and who live mainly in the Iraqi province of Diyala which borders Iran.

The defendants are accused of forcibly displacing Faily Kurds, confiscating their property and belongings, as well as using them for chemical weapons experiments and as human shields on the battle front during the Iran-Iraq war from 1980 to 1988.

Chemical Ali, Saddam's cousin, has already been condemned to death for genocide over the so-called Anfal campaign against Kurds in the 1980s and for war crimes and crimes against humanity over the crackdown on Shiites during their ill-fated 1991 uprising after the first Gulf war.

He, Hassan and Aziz are also all on trial for crimes against humanity over the 1992 execution of 42 Baghdad merchants who were accused of speculating on food prices when Iraq was under punishing UN sanctions.

Aziz, 72, is a Christian who also served as foreign minister under the now executed Saddam and became regarded as the Iraqi dictator's mouthpiece to the outside world.

He turned himself in to US forces in April 2003 after they overthrew Saddam's regime, but his son last year complained that he was being held in very bad conditions and was suffering from a variety of ailments.

Hassan, a member of the Baath party from the very first day, is a half-brother to Saddam and was interior minister and an adviser to the Iraqi leader.

Abed Hamud, the head of Saddam's office, also held the post of deputy prime minister under his regime.

Saddam himself was hanged in December 2006 for the killing of 148 Shiite villagers after an attempt on his life in 1982.