The Human Rights Law Centre has called for urgent reform of national security laws to prevent a repeat of the "unprecedented" situation in which a former Australian intelligence officer was jailed in "complete secrecy".
Witness J, as he has come to be known, spent 15 months locked up in Canberra's prison after being prosecuted and sentenced behind closed doors in the ACT courts.
The case only came to public attention after he had been released, and the little information that is available shows he had pleaded guilty to charges related to "mishandling classified information".
Former federal attorney-general Christian Porter has said the information was "of a kind that could endanger the lives or safety of others".
The case is now being examined by the independent national security legislation monitor, Grant Donaldson SC.
He will consider whether the National Security Information Act, under which the proceedings were closed to the public, was used in a way that was "proportionate to threats to national security".
In a new submission to the monitor, made public on Tuesday, the Human Rights Law Centre said the arrangements in the Witness J case were reminiscent of what might happen in authoritarian states.
The centre argued that total secrecy had "no place in liberal democracies like Australia".
"While we acknowledge that partial secrecy has a legitimate place in judicial proceedings in certain limited circumstances, we believe that the complete secrecy imposed in the Witness J case is wholly unprecedented," the submission said.
"It should never be repeated. We urge the [monitor] to recommend that the NSI Act be amended to include adequate safeguards."
The centre put forward seven recommendations in its submission, including that "minimum standards of openness" be added to the legislation.
An "open justice advocate" should also be allowed to argue for transparency during cases where the NSI Act was invoked, the submission said, while courts should publish reasons explaining the need for any closure orders made under the legislation.
The centre's other recommendations included the establishment of a "library of secret judgments", which would be reviewed periodically "to ensure maximum openness".
"It is difficult to conceive of a situation where total secrecy, and not only partial secrecy, will be justified," the submission said.
Kieran Pender, a senior lawyer at the centre, said there was currently an "open justice deficit at the heart of the NSI Act".
He said open justice was "a fundamental democratic principle" that ensured accountability and public confidence in the justice system.
"While, in limited circumstances, narrow exceptions to open justice might be justifiable, we should never have a situation where a person is charged, prosecuted and sent to prison entirely in secret," Mr Pender said.
"There is no place for secret trials in Australia.
"The NSI Act must be urgently amended to ensure the secrecy which shrouded the Witness J case can never be repeated."
The window to make written submissions to Mr Donaldson's review of the case closed last Friday.
He plans to hold a public hearing in Canberra on June 9, with details to be provided closer to the date.
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