Hicks’ military lawyer, Major Michael Mori says his client could be sentenced to death if a new military commission system passes through the United States Congress.
But a spokesman for Australian Attorney-General Philip Ruddock says although the new legislation will permit the death penalty, the US government's given repeated assurances it won't seek it for Hicks.
David Hicks has been in US custody at Guantanamo Bay in Cuba since January 2002 a month after he was captured fighting among Taliban forces in Afghanistan.
The 31 year old has been charged with aiding the enemy, attempted murder and conspiracy.
He was due to have been tried by a military commission but the US Supreme Court has ruled the commissions unlawful.
The decision forced the US Administration to revamp the process.
David Hicks’ father, Terry, says verbal statements aren't enough and he'd like to see the government get something on paper to confirm it's not going to be sought.