Among other issues, Human Rights Watch and Amnesty International have expressed unease about limits on the ability of the accused to mount a defence, the burden of proof, political sway over the court and use of the death penalty.

Questions also surround the fact the Iraqi government has passed new laws governing the court, but has not yet brought them into force. Those new statutes could take effect in the next few days, or after the trial begins, raising further doubts about the clarity of procedures.

Saddam and seven others are due to appear in court on October 19 on charges of premeditated murder in the deaths of more than 140 Shi'ite men from the village of Dujail, north of Baghdad, following a failed attempt on the then-president's life in 1982.

In an 18-page report on Sunday, New York-based Human Rights Watch questioned trial preparations, including the amount of time the defence had been given to study evidence and its access to witnesses, and said proceedings might not be free or fair.

"We have grave concerns that the court will not provide the fair trial guarantees required by international law," said Richard Dicker, director of the group's international justice program.