The trial of Australian national David Hicks at Guantanamo Bay was a charade that served to corrode the rule of law, Australia's top legal body has said.
David Hicks spent more than five years in Guantanamo Bay
The Law Council of Australia called government support for the US military tribunal process shameful.
In a report on the issue, the council drew a parallel with the case of detained Indian doctor Mohamed Haneef.
Both cases had an "Alice in Wonderland quality" to them, Law Council President Tim Bugg said.
David Hicks was arrested in Afghanistan in 2001 and spent more than five years in the Guantanamo Bay detention camp.
At a military tribunal earlier this year he admitted supporting terrorism and, under a plea deal agreed with prosecutors, was jailed for seven years.
All but nine months of the sentence were suspended and he has now been returned to Australia.
Prime Minister John Howard's government had faced mounting public criticism over its failure to secure his release.
'Veneer of due process'
According to the report prepared by lawyer Lex Lasry, aspects of Hicks' plea agreement appeared "an attempt to protect the credibility and interests of the US government".
The deal also meant that his tribunal became "a contrived affair played out for the benefit of the media and the public".
It was "designed to lay a veneer of due process over a political and pragmatic bargain", the report said.
Mr Lasry called the Howard government's support for the tribunal process "shameful" and said Australia's moral authority had been diminished by it.
"Ultimately there has been no benefit from this process; only a corrosion of the rule of law," he wrote.
Haneef was arrested under new anti-terrorism laws in Brisbane
Law Council President Tim Bugg, releasing the report, also highlighted the case of detained Indian doctor Mohamed Haneef.
Dr Haneef has been charged with providing "reckless support" for a terrorist organisation in connection with last month's suspected failed bomb attacks in the UK.
A Brisbane court awarded him bail, but the Australian government then revoked his work visa in order to keep him in detention under immigration laws, prompting outcry from civil liberties groups.
"There's an 'Alice in Wonderland' quality to both these cases - 'First the sentence, then the verdict'," Mr Bugg said.
"Mr Hicks and Mr Haneef both know what that feels like," he said.