Mr Collaery, a Canberra lawyer and former territory politician, is set to stand trial in the ACT Supreme Court accused of five offences.

He is pleading not guilty to four counts alleging he breached the Intelligence Services Act by sharing protected information about the Australian Secret Intelligence Service.

He is also fighting a single charge of conspiring with his former client, the ex-spy known as Witness K, to do so.

The allegations concern the exposure of a 2004 espionage operation, in which Australian spies bugged a government building in East Timor.

Australia was negotiating with its impoverished ally over lucrative oil and gas resources at the time.

Mr Collaery has now been before the courts for more than three years, with several of what Justice David Mossop has described as fronts in a greater war creating a series of delays in the case.

The most recent development of significance came last month, when the ACT Court of Appeal set aside an order Justice Mossop had made to ban public disclosure of certain information that was likely to be given at Mr Collaery's eventual trial.

Justice Mossop had made this order, sought by former federal attorney-general Christian Porter, under national security legislation.

Its effect was that Mr Collaery's trial would be largely conducted in secret, but the Court of Appeal's ruling in October means much more significant portions of the case will now be aired openly.

In a judgment summary, three Court of Appeal judges said secrecy posed a very real risk of damaging public confidence in the criminal justice system, while open justice deterred political prosecutions.

Some matters will still be shielded from public view, however, and lawyers for the current federal Attorney-General, Michaelia Cash, appeared in the Court of Appeal on Tuesday to seek redactions to the reasons it will publish to explain its ruling on the secrecy issue.

Senator Cash's barrister, Anna Mitchelmore SC, said she would need to make submissions about "specific redactions" that could not be discussed in open court.

The court heard Mr Collaery accepted some of these were necessary and his barrister, Christopher Ward SC, indicated he would press for "insertions" in place of some of the remarks that are set to be removed.

Both barristers made carefully considered comments during the half-hour or so the court was open, aware of the fact the secrecy provisions still in operation prevented them from saying much.

Chief Justice Helen Murrell ultimately closed the proceedings to the public in order to allow the lawyers to speak more freely.

Human Rights Law Centre senior lawyer Kieran Pender, who observed the proceedings prior to the closure, called for an end to the case.

"Secrecy in the Bernard Collaery case erodes public confidence in the justice system and opens the door to political prosecutions," Mr Pender told The Canberra Times.

"That's what the ACT Court of Appeal said last month.

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"People who tell the truth about wrongdoing should be protected, not punished.

"The next step in this sorry saga should be to drop the charges altogether, not to argue for more secrecy, at a secret hearing, about a judgment that said no to a secret trial."

That seems unlikely to happen, with Commonwealth Director of Public Prosecutions Sarah McNaughton SC publicly backing the continued prosecution of Mr Collaery as recently as last week.

The issue of the redactions will be determined at a later date.

Senator Cash may yet head to the High Court to challenge the decision to set aside Justice Mossop's secrecy order.

She has until Wednesday to file an application for special leave to appeal in that court.

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