Roberts-Smith says failed court case cost Kerry Stokes 'upwards of $30m'

War veteran Ben Roberts-Smith has revealed how much his failed defamation case cost the billionaire who helped bankroll it and said he does not regret "a single thing" in his military career, during a lengthy media interview conducted as he awaits a trial over alleged war crimes.

The Victoria Cross recipient continued to emphatically deny wrongdoing and insisted he always adhered to the rules of engagement in a two-and-a-half hour conversation with 2GB, owned by Tapt Media.

He has been charged with five counts of the war crime murder, relating to his deployments with the Special Air Service Regiment in Afghanistan between 2009 and 2012.

Prosecutors allege the victims were unarmed Afghan nationals not taking part in hostilities, shot by Mr Roberts-Smith or by soldiers acting under his orders.

The case will return to court in December.

"I'll maintain the position I have always maintained, that I will fight these allegations and their charges in their entirety," he said during the interview.

The veteran said he had no regrets about his military career, when asked by host Ben Fordham if there was anything he would change, even if it was not criminal.

"I wouldn't change a single thing," he replied.

"I would do it all exactly the same way, because I know I did the right thing, I know I was prepared to die for this country every time I went outside the wire, and I know I did whatever I could to keep my mates alive, but I never broke the rules of engagement."

Court case cost Stokes 'upwards of $30m'

Mr Roberts-Smith conceded that he was "naive" about the civil court system, after he lost a high-stakes defamation case against Nine newspapers.

Those proceedings ended with a Federal Court finding that, on the balance of probabilities, allegations he was responsible for, or complicit in the deaths of four detainees in Afghanistan, were substantially true.

His case was financially backed by billionaire media mogul Kerry Stokes, who Mr Roberts-Smith said had supported him from "day one" including by paying legal bills.

"I don't have an exact figure, but I would say it would have to be upwards of 30 million," he said.

Mr Roberts-Smith told Fordham he was not able to speak about the criminal proceedings or specific allegations, but wanted to put "a couple of facts on the table".

"This is not me trying to convince anyone of anything," he said, urging people to make their own minds up and making multiple references to "punters".

Roberts-Smith says picking jury could be tough

The veteran said he had "questions" about how the criminal proceedings have unfolded, once again took aim at the public nature of his arrest at Sydney Airport, and reflected on what he said were high levels of support from "the public at large".

Acknowledging his criminal trial may be more than five years away, Mr Roberts-Smith said he was unsure whether it would be possible to find 12 jurors who had not formed an opinion, one way or the other, due to extensive media reporting of the allegations.

"How do you find people that don't already have a position?" he asked.

"Just in that sense alone, can there be a fair trial? I can't answer that question and I'm sure that argument is going to be had, and we'll find out whether they think it can or can't."

But he said he was "comfortable" with the idea of having 12 "normal people" listening to the case.

"I know we will be able to explain to them the things they don't understand about the military enough that when they hear the actual evidence, they will understand where all the holes are and how it's come about."