Secret Defence documents obtained under freedom of information laws show an Australian officer, Major George O'Kane, was far more deeply involved in the operations of Abu Ghraib prison when terrible abuses of prisoners occurred than previously revealed.

The documents, which include extensive interviews with Major O'Kane when he returned from Iraq in 2004, reveal that as a military lawyer embedded with the United States he was a primary author of the manual for processing prisoners in Iraq.

Abu Ghraib detention ... the record.

He also advised on the legality of interrogation techniques being used on at least one detainee. Major O'Kane was instructed to deny access to the Red Cross to nine ''High Value Detainees'' during their January 2004 visit because the prisoners were undergoing active interrogation and, according to the US view, fell under the exemption of ''imperative military necessity''. This view was contentious.

After his return he told superiors he was aware of rumours that the US had ordered an internal investigation of Abu Ghraib and it had something to do with photos, though his knowledge does not appear to have extended beyond a conversation with a US officer who assured him it was being investigated.