A judge has described "extraordinary" moves by federal government lawyers to block Bernard Collaery from briefing one of Australia's top barristers in the East Timor espionage case as "disturbing".
Justice John Burns made the remarks in an ACT Court of Appeal judgment published on Tuesday, saying the Commonwealth's actions had been "unfair".
Mr Collaery, a lawyer and former ACT attorney-general, is fighting five charges alleging he breached the Intelligence Services Act by sharing protected information and conspiring with former spy Witness K to do so.
The allegations concern the pair's roles in the exposure of a 2004 operation in which spies bugged a government building in the impoverished nation of East Timor to give Australia an advantage in negotiations over lucrative oil and gas resources.
Mr Collaery's case is heading towards a trial in the ACT Supreme Court, but how much of the proceedings will be conducted in open court remains to be seen.
He is currently appealing against a ruling that would result in significant parts of the trial being held behind closed doors to prevent public disclosure of what Commonwealth Attorney-General Christian Porter has deemed to be "national security information".
The appeal was set to be the subject of a hearing early next week, but Mr Collaery successfully applied late last month to have those dates vacated.
In his reasons for granting the application, published on Tuesday, Justice Burns said Mr Collaery had seen "eminent senior counsel" Bret Walker SC at "a social function" a few days before Christmas.
At that event, Mr Walker, the former independent national security legislation monitor, agreed to work on the appeal for Mr Collaery on a pro bono basis.
Mr Collaery's representatives promptly phoned and emailed the Australian Government Solicitor on December 23, requesting that Mr Walker be approved under the National Security Information Act to access confidential material relevant to the case.
They requested that any issues with this proposal be raised "as soon as possible", given the appeal was at that point set to be heard in less than two months.
Later the same day, Mr Collaery's team also indicated that it would seek to have the hearing pushed back because Mr Walker was unavailable to appear in court on the listed dates.
Government lawyers took almost a month to respond in detail, writing back that they were still considering the matter because they needed to limit the disclosure of "highly sensitive national security information ... to active and necessary participants".
They proposed to wait and see whether the Court of Appeal would postpone the hearing, then decide whether to approve Mr Walker.
Mr Collaery's team quickly replied that Mr Walker could still play an active role in preparing the appeal, regardless of whether he appeared in court, describing the delay in deciding on the silk's approval as "unfair" when the matter could still proceed as listed.
The government finally agreed to approve Mr Walker on January 25, less than three weeks before the scheduled appeal hearing.
In deciding to vacate the hearing dates and allow Mr Collaery more time to bring Mr Walker up to speed, Justice Burns took a dim view of the government's late approval.
"Any benefit to the appellant in briefing Mr Walker with regard to the appeal ... was likely to be significantly reduced, if not lost entirely," the judge said.
"I consider this to be unfair on the appellant."
Justice Burns said the Commonwealth Attorney-General had "extraordinary" power to "veto" an accused person's choice of counsel under the National Security Information Act.
This power, the judge said, "should not be exercised in order to gain a forensic advantage".
"Nor is it any part of the role of the Attorney-General to base his or her decision on whether he or she thinks that it is necessary for the accused to instruct that particular lawyer," Justice Burns said.
"The email from [the Australian Government Solicitor] ... carries a disturbing suggestion that those who represented and advised the Attorney-General perceived that their satisfaction at the necessity for Mr Walker to be briefed by the appellant was in some way relevant. It clearly was not."
New dates for Mr Collaery's appeal are yet to be determined.