A commission of inquiry has found the death of a soldier who was killed during a live ammunition training exercise was avoidable.

The death of a soldier and the wounding of another when they moved behind targets during a night training exercise using live ammunition could have been avoided, Defence says.

But it’s not spelling out just how the tragedy occurred.

The report of the commission of inquiry won’t be released at the request of the family of Lance Corporal Mason Edwards, 30, a member of the 2nd Commando Regiment.

He died after being shot in the head in October 2009 as special forces soldiers exercised at the Cultana Training Area in South Australia ahead of deploying to Afghanistan.

Another unnamed soldier received fragment wounds to his arm.

Defence said the inquiry concluded the accident could have been avoided.

It also said Lance Corporal Edwards wasn’t responsible for his own death as he was unaware of the danger he was in.

Defence says it’s taken steps to improve safety by implementing the report’s recommendations. That includes changes to briefing procedures before live-fire exercises, to conduct of such exercises and to training areas.

Defence also took administrative action against six soldiers, with unspecified “adverse consequences” imposed on three.

Under a policy established under Labor, the government consulted Lance Corporal Edwards’ family about whether the inquiry report should be released.

After considering their views, Defence Minister David Johnston decided not to publicly release the report.

“Defence deeply regrets the death of Lance Corporal Edwards and action has been taken to reduce the likelihood of a tragedy of this nature happening again,” Defence said in a statement.

Lance Corporal Edwards joined the army in 2004 after first completing a bachelor of arts in psychology degree at the University of Queensland.

He was one of the first through the special forces direct recruiting scheme. Regarded as an exceptional soldier, he was preparing for his third deployment to Afghanistan when he was killed.