Lawyers for former military lawyer David McBride withdrew an application to have him protected under whistleblower laws after the Commonwealth moved to suppress expert evidence.
Two experts were set to support McBride's case but commonwealth lawyers sought to have their testimony quashed under public interest immunity laws.
The laws suppress information that would prejudice the public interest if they were made public.
McBride said there was little prospect of success without their evidence.
"The government played the national security card to the absolute hilt," he told media outside the ACT Supreme Court on Thursday.
His lawyer Mark Davis said it's common for sensitive material - such as what may have been included by the two experts - to come before the courts.
The judge has the power to then close the court to the public and media.
"If I could show it to you, the material is not that controversial," Mr Davis told media.
"But you would think it's identities of agents or codes."
McBride is now facing a jury trial on five charges, including the unauthorised disclosure of information, theft of commonwealth property and breaching the Defence Act.
He shone a light on allegations of Australian special forces committing war crimes in Afghanistan, disclosing classified documents to the media throughout the middle of the last decade.
The resulting Brereton report into the allegations found credible evidence of war crimes by Australian special forces while serving in Afghanistan, including 39 murders, executions and allegations of torture.
The Human Rights Law Centre said the fact McBride is the only person facing prosecutions after allegations of war crimes came to light was an indictment on Australia's whistleblower laws.
"This ongoing prosecution makes a mockery of the Brereton report and is a stain on Australia's international reputation," senior lawyer Kieran Pender said.
McBride's hearing put Australia's whistleblower protections to the test after Attorney-General Mark Dreyfus promised reform in the area.
Mr Dreyfus is being urged to drop charges after he discontinued the prosecution of whistleblower Bernard Collaery earlier this year.
Mr Collaery had been facing charges for four years after he was accused of leaking classified information about an alleged Australian spying operation in East Timor.
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