Financial backers of Ben Roberts-Smith are fighting what lawyers say is a “trawling exercise” to further uncover their role in the former soldier’s failed defamation proceedings.

Billionaire media boss Kerry Stokes is among those facing subpoenas filed in the Federal Court, as Nine Entertainment seeks indemnity costs from the disgraced SAS corporal’s third-party backers.

Mr Roberts-Smith’s lawsuits were funded partially by the Seven Network, which is chaired by Mr Stokes, as well as the billionaire’s private company Australian Capital Equity (ACE) on a loan agreement.

Justice Anthony Besanko dismissed Mr Roberts-Smith’s lawsuits in June, finding reports in The Sydney Morning Herald, The Age and The Canberra Times alleging he engaged in war crimes while deployed with the SAS in Afghanistan were substantially true.

Lawyers for the Nine-owned outlets will argue Seven played a significant role in the case from the very start by enabling the former soldier to hire legal representation he wouldn’t normally be able to afford.

Barrister Nick Owens argued on Thursday some 8600 emails between Mr Roberts-Smith, his legal team and Seven commercial director Bruce McWilliam suggest they were more than just observers of the case.

“I think the litigation went through just over 100 days, that seems to be an average of about 86 emails a day,” Mr Owens told an interlocutory Federal Court hearing.

“On its face we say that provides a very strong presumption … there is something more than mere observation going on.”

Subpoenas have been issued to Seven, ACE, Mr Stokes, Mr McWilliam and law firm Herbert Smith Freehills.

Neil Young KC, representing those respondents, said the sheer number of emails itself does not suggest any instruction or guidance was being provided as to how the case should run.

He said many of the emails may also be in reference to company operations at Seven, where Mr Roberts-Smith was also employed, and only contain “glancing” reference to the case.

Mr Young contested the scope of subpoenas facing Mr Stokes and others as “far too wide”, particularly considering they were not parties to the defamation case.

“It’s quite plain that they have no legitimate forensic purpose within the meaning of the authorities and they are effectively undertaking a trawling exercise,” he told the hearing.

“But that’s the approach adopted, consciously, because they want to cast a dragnet.”

Mr Roberts-Smith has appealed the outcome of his defamation lawsuits, arguing the judge’s findings were improbable, speculative and based on unreliable witnesses.

He has accepted he should pay costs on an indemnity basis from March 17 of 2020, but disputes he should do so from the date the proceedings commenced on August 15 of 2018.

It is not in dispute that Mr Roberts-Smith does not have the means to pay the media giant’s defence costs himself, likely to be in the tens of millions of dollars.

– AAP