Justice David Mossop raised this possibility in the ACT Supreme Court on Friday, during the latest instalment of the long-running legal saga.

Mr Collaery, a Canberra lawyer and former ACT attorney-general, is awaiting trial in that court on five charges laid over his role in the exposure of a 2004 Australian espionage operation in East Timor.

He denies allegations he broke the law by sharing protected Australian Secret Intelligence Service information with journalists.

The 77-year-old is also pleading not guilty to a charge of conspiring with his former client, the ex-spy known as Witness K, to breach the law by sharing such information with the government of East Timor.

More than three years after the case against Mr Collaery began, it is still unclear when the trial will actually be held.

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Friday's proceedings focused on whether federal Attorney-General Michaelia Cash should be able to update so-called "court-only evidence" her counsel says is relevant to the matter.

This evidence, which the Commonwealth considers so secret not even Mr Collaery or his lawyers have been allowed to see it, was prepared between 18 months and two years ago.

Justice Mossop, the trial judge, is yet to look at it.

He will, in time, be required to rule on whether it should be kept hidden or whether the Commonwealth will have to deal with it in open court should it choose to.

Jeremy Kirk SC, a barrister for Senator Cash, told the court on Friday that the Attorney-General should be allowed to update the evidence because some of it was now outdated and many of its authors had retired or moved into new roles.

But Christopher Ward SC, for Mr Collaery, argued the Attorney-General should simply remove anything that was no longer accurate, and nothing else should be allowed to change.

Justice Mossop questioned whether recent events that could have implications for Australia's national security might also become relevant considerations in the trial if the so-called court-only evidence was capable of being updated.

He listed examples like Justice Paul Brereton's inquiry into war crimes allegedly committed by Australian soldiers overseas, the diplomatic row between Australia and France over submarines, and "the resignation of the minister who was the attorney-general because he was accepting anonymous donations".

"Stuff happens in the world," Justice Mossop said.

The judge indicated he would give his decision on whether the "court-only evidence" could be updated next Tuesday afternoon.

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