A top military law expert says the allegations about Ben Roberts-Smith's conduct while serving in Afghanistan are "significant" and must be publicly addressed.

Associate Professor David Letts, director of the Centre of Military and Security Law at the ANU College of Law, said the incidents described in a Fairfax Media investigation had raised "very significant problems" for the Australian Defence Force.

Professor Letts said that while there may be some aspects of the Inspector-General's investigation into the Special Air Service Regiment's operations that must be kept secret for reasons of military security, "as much as possible" of its findings should be released.

Ben Roberts-Smith has denied all of the allegations against him. Credit:Jay Cronan

He said the public interest in the matter was such that openness and transparency was needed, and would help interested parties to accept the findings of the secretive inquiry.