The federal Opposition leader, Kim Beazley, says he has obtained documents which contradict claims the Foreign Affairs Department was simply a receiving point for messages in the AWB affair.
Several Foreign Affairs officials have testified at the Cole Inquiry that their role was to act as "a postbox" for AWB's contracts with the United Nations, not to investigate the contracts for breaches of sanctions.
Mr Beazley has released what he says is a Customs document approving AWB's contracts, and stating that they comply with UN rules on Iraqi sanctions.
"That document is signed by a Foreign Affairs official, effectively the delegate of the Minister.
"That is not the signature of somebody with the status of a postman - that is the signature of somebody with approval authority.
"And those Ministers now seek to evade their responsibility.
"They cannot do it."