The high-stakes defamation trial of war veteran Ben Roberts-Smith has been paused for at least a month due to Sydney’s COVID-19 lockdown.

Justice Anthony Besanko adjourned the case on Tuesday for mention in three weeks, with a view to the trial starting again one week later.

It comes after the Federal Court heard three weeks of evidence and Mr Roberts-Smith’s legal team closed his case on Monday.

The court has been told defence witnesses due to travel to Sydney would either be barred from returning home or endure quarantine impediments.

Mr Roberts-Smith is suing The Sydney Morning Herald, The Age, The Canberra Times and three journalists over reports published in 2018 which contained serious allegations about his deployments to Afghanistan.

The Victoria Cross recipient has denied allegations of unlawful killings in Afghanistan, bullying of his former soldier colleagues in the Special Air Service Regiment and committing an act of domestic violence against his then-lover in 2018 at a Canberra hotel.

Mr Roberts-Smith’s legal team closed his case on Monday after three weeks of evidence, about a third of which he spent under tense cross-examination in the witness box.

But Nicholas Owens SC, the barrister for two of the newspapers, said on Monday the lockdown meant interstate defence witnesses would either be barred from returning home or face quarantine impediments if they travelled to Sydney.

The judge agreed the real issue was not the expiry of Sydney’s stay-at-home orders, but the hard borders with other states and self-isolation requirements.

“In my opinion, it would not be a fair or proportionate exercise to enforce the attendance of these witnesses in the circumstances and at this point in time,” Justice Besanko told the court on Tuesday.

Mr Roberts-Smith’s barrister, Bruce McClintock SC, conceded on Monday the adjournment was “a tragedy”, but said he wasn’t willing to cross-examine over video link and witnesses had a right for their lives not to be “completely upended”.

Publisher Nine Entertainment is relying on a truth defence and will call 21 former or current SAS operatives, Mr Roberts-Smith’s ex-wife Emma Roberts, and the woman with whom he had an affair.

A group of people known as “the Afghan witnesses” will also give evidence over video link from Afghanistan at some point in the proceedings.

Mr Owens said on Tuesday the security situation in Afghanistan was “deteriorating rapidly” and Nine is concerned to have the evidence of the witnesses, currently in Kabul, heard as soon as possible.

They are expected to speak about the death of a farmer named Ali Jan, who Mr Roberts-Smith is accused of interrogating, handcuffing and kicking over a cliff during a 2012 mission in the village of Darwan.

Nine alleges he then entered into an agreement with other soldiers that Ali Jan be executed, before covering up the conduct by making it look like he was shot during a legitimate engagement.

Mr Roberts-Smith, 42, has told the court a man shot dead during that mission was a suspected Taliban “spotter” who had been hiding in a cornfield.

The adjournment will cause a blowout in the trial’s lengthy duration, which was already estimated to take up to 10 weeks.

-ABC