The claims emerged in the sensational final stages of a hearing into whether Australian wheat exporter AWB illegally channelled cash to the regime of Saddam, who is on trial in Iraq for the genocide of 182,000 people in a 1987-88 campaign against the Kurds.

The nine-month-old probe on Friday saw a damning internal document from AWB which revealed that executives knew the Iraqis wanted foreign currency in 2001 to build 2,000 concrete burial bunkers.

"The bunkers will have cement walls and floors so they are actually designed for burying the Kurds," said an email from AWB executive Daryl Borlase to several other AWB staff.

"Under the cement?? They intend to build them with fumigation capability so the mind boggles as to whether they are fumigating insects or any other pest that pisses them off," the email read.

Inquiry lawyer John Agius questioned AWB's former managing director Andrew Lindberg about the email, asking if the firm's staff knew of the atrocities that Saddam's government was capable of while it was passing on kickbacks.

"Would you agree ... there were personnel within AWB (who knew) what the Iraqi regime was capable of doing?" Agius asked.

Lindberg said: "I think it is open for you to draw that inference."

Agius said he was asking the question as the inquiry was tasked with weighing "whether or not it might be said AWB committed an offence under terrorism offences in the (Australian) criminal code".