Saddam, hanged on December 30 after being found guilty of crimes against humanity in a separate trail, had been chief accused in the genocide trial.

But Judge Mohammed al-Oreibi al-Khalifah said at the start of the session that the Iraqi High Tribunal had dropped all charges against him.

The ousted despot had been a familiar sight in the dock since proceedings began on August 21 in Baghdad, showing defiance from his front-row seat and frequently railing against court officials and witnesses.

On Monday, the seat was empty, with Saddam's six co-accused declining to occupy it.

All face the death penalty should they be found guilty of slaughtering 182,000 Kurdish villagers in the 1980s.

Prosecutor Munqith al-Faroon produced an audio tape which he said contained the voice of Saddam giving the go-ahead to use chemical weapons in places crowded with Kurds.

"I will take responsibility for using the chemical weapons. No one can direct the strike without my approval," the voice purported to be that of Saddam is heard saying on the tape.

"It is better to use this weapon in crowded places to be effective on as many people as possible," the voice is heard saying.

"We have to remove the Kurdish people to other governorates and countries, to end the Kurdish nationality and to stop saboteurs' acts. We have to allow them to live and work in Tikrit so that they will become Arabs."

Faroon said the tape proved the former regime intended "to fight Kurdish culture, it is a genocide."

The voice is also heard saying, "The Kurds are very aggressive people, all their characteristics are just like the Iranian ... Whenever you see saboteurs acts, cut their heads off immediately."

Faroon did not reveal when the tape was recorded nor to whom Saddam was speaking.

The ongoing case centres on the killing of 182,000 Kurdish villagers during the so-called Anfal campaign, which ran between 1987 and 1988.

Chief among the co-accused is Ali Hassan al-Majid, the former defence minister and a first cousin of Saddam who became widely known as "Chemical Ali" and who is charged with genocide.

His five co-accused have been charged with war crimes and crimes against humanity.

Faroon during Monday's session also presented a video clip that he says showed Ali planning chemical attacks.

"I will attack them with chemical weapons," Ali is heard shouting twice in the video.

Pictured wearing a military uniform, Ali also expresses complete disregard for expected international criticism.

"To hell with the international community," he shouts.

The footage also showed pictures of children and women killed by chemical weapon attacks.

"We see families... men, women, children... weeping. I want the whole world to look at these pictures, these children, these human bodies," Faroon said.

"There is a child here on the chest of his mother. Take a look at this child and the burns on his skin. Are they saboteurs, agents for Iran?"

While the video was being played, the former defence minister, dressed in traditional Arab garb, listened silently to the prosecutor.

But before the trial was adjourned until Thursday, Ali in an outburst yelled that the trial was "political".

"I will remain silent and you can decide the charges against me," he said.

He also referred to "martyr Saddam" before the judge cut off the microphone in the courtroom.

Faroon presented a document allegedly signed by Taher al-Ani, the former governor of the northern city of Mosul, agreeing to a directive from Ali to execute 10 Kurds.

Ani however denied it was his signature on the document.

Iraqi authorities and human rights group accuse Saddam's regime of having meticulously carried out military attacks, some using chemical bombs, against the Kurds.

The accused claim the campaign was a necessary counter-insurgency operation against Kurdish guerrillas who had sided with Iran against Saddam at the peak of the Iran-Iraq war in 1980-88.