REVILED sex predator Robert Fardon is a free man after the State Government last night abandoned an 11th-hour bid to keep him behind bars.

Queensland's highest court yesterday dealt the Government a crushing double blow, ordering the immediate release of the 65-year-old serial rapist.

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The Court of Appeal in Brisbane also ruled invalid the Government's new sex offender laws, which allowed Attorney-General Jarrod Bleijie to keep sex offenders behind bars in prison despite court orders.

The decision means leaves the new laws are now in tatters. They cannot be applied unless re-drafted or until a High Court application, which would occur only in the rare event the Government is given special leave for the case to be heard.

Mr Bleijie is considering appealing in the High Court.

The Court of Appeal, comprising justices Kate Holmes, John Muir and Hugh Fraser, unanimously dismissed Mr Bleijie's appeal to reverse last month's Supreme Court decision to grant Fardon supervised release.

media_camera A-G livid as serial rapist walks free

The court said Mr Bleijie's claim that Fardon remained an unacceptable risk to the community was "opaque" and lacked "supporting evidence".

The court also ruled that sections of the Criminal Law Amendment (Public Interest Declarations) Act 2013 were invalid.

In its written decision, the Court of Appeal said the laws were "repugnant" and eroded the integrity of courts to make decisions and in effect "undermine the authority of orders of the Supreme Court".

"These (legal) amendments are within that exceptional category of legislation which is invalid on the ground that it is repugnant to (the) institutional integrity of the Supreme Court,'' the court said.

Lawyers for Mr Bleijie immediately applied to have the release order stayed pending further legal argument.

But late yesterday that application was withdrawn, paving the way for Fardon's immediate release.

No reason was given for the withdrawal, with Justice Muir adjourning the hearing without submissions being made.

While Fardon is technically free to live anywhere under supervision, it is expected he will for now live in housing outside Wacol Correctional Centre, in Brisbane's west.

The site, dubbed the "dangerous sex offender precinct'', is where Fardon lived when he was first released in 2006.

One of Fardon's victims, Sharon Tomlinson, burst into tears after the announcement. Outside court her tears turned to rage.

"This man will reoffend and someone (innocent) will have to pay the price. (Crime) survivors and the community are no longer safe," she said.

"I hope he's not coming after you or someone you love."

Barrister Dan O'Gorman, for Fardon, said his client would be relieved the Court of Appeal had ruled in his favour.

He said Fardon had great respect for the courts and was committed to abiding by the strict conditions he must obey as part of his supervision order.

Those conditions, imposed by Justice Peter Lyons on September 27, include GPS tracking and a drug and alcohol ban.

Sources last night told The Courier-Mail Mr Bleijie was "nothing short of livid".

Mr Bleijie said the Government would continue to do everything it could to keep people like Fardon in jail. "We want to make sure we protect the women and the children of this state from these vicious, nasty sexual predators,'' he said.

Fardon has waged a 10-year battle for freedom after serving the full sentence he received for the rape, assault and sodomy of a woman in 1988.

The violent assault happened when Fardon was released from jail on parole after serving eight years of a 13-year sentence for the rape and assault of a girl, 12, and wounding of her 15-year-old sister.