Bernard Collaery has lamented "the now fragile state of our democracy" and vowed to "fight on for justice" as a pre-trial hearing takes place behind closed doors.
The Canberra barrister has pleaded not guilty to charges that he breached national security laws by communicating Australian Secret Intelligence Service information and conspiring with his former client, the ex-spy known as Witness K, to do so.
The charges concern the exposure of an Australian spying operation, in which East Timor's cabinet rooms were bugged as the tiny island nation negotiated with Australia over oil and gas reserves.
Witness K has also been charged and is being dealt with in separate proceedings.
Mr Collaery, a former ACT attorney-general, will eventually stand trial at a date that is yet to be fixed.
On Monday, a pre-trial hearing listed for seven days began in the ACT Supreme Court. The hearing will largely deal with the issue of how much of Mr Collaery's trial will be conducted in open court, given it will cover national security issues.
Justice David Mossop made an order to close the court almost immediately on Monday, permitting a limited number of people to remain. They included Mr Collaery, the Commonwealth Director of Public Prosecutions, Commonwealth Attorney-General, legal representatives for those parties, court staff and witnesses deemed necessary to resolve the issues at hand.
Justice Mossop stressed that this was not the final hearing of the charges against Mr Collaery, and that national security laws meant the court had no discretion in deciding who could attend these pre-trial proceedings.
Mr Coallery, in a statement handed to reporters as the court was closed, said these were "sad times".
"I have spent a great part of my life in the law serving our legal system," he said.
"The law has been my life. I'm now an accused in a court I have long regarded as my second home.
"I am unable to say much and you are unable to report much. This is the state of our now fragile democracy."
Mr Collaery went on to express his hope that his case would one day be examined in a royal commission.
"I want to say this today to those people within the system who I know objected to what was going on: I salute you for standing up to be counted. You are not alone," he said.
"I hope that there will be a royal commission in my lifetime and you will be recognised for being true in your service to our country."
Mr Collaery also said he was grateful to his legal team and his supporters.
Protesters have regularly turned up at the ACT courts before Mr Collaery's appearances to demand that his prosecution be dropped.
Dozens did so again on Monday and cheered Mr Collaery as he arrived.
"These are sad times for more than myself and I'll fight on for justice," Mr Collaery's statement concluded.