Martin Hamilton-Smith, from the Australian Special Air Service Association, said the defamation judgement would be felt widely throughout the organisation. 

"This will be a very disappointing day not only for Ben Roberts-Smith, but for everyone involved," he told the ABC News Channel.

"This is a very proud regiment, it's one of the finest units in the Australian order of battle, these men have served us bravely, from Malaysia, Borneo right through Vietnam, through to the Middle East.

"I'm very concerned, as the national chairman for our veterans and their families.

"It's been very traumatic for a group of soldiers, 99.9 per cent of whom did nothing more than fight bravely for their country.

"And they're being re-traumatised after going through a difficult war now, with all of these matters."