Concerns have been raised over laws that allow for convicted terrorists to be detained after they’ve served their sentence if they’re deemed to be at risk of reoffending. 

Any further detention should only be used as a last resort and in light of strong evidence about the prospect of a future offence, the Australian Human Rights Commission in evidence given to an inquiry into the laws on Wednesday.

“Ensuring that laws in this area protect our national security, but also show a strong respect for human rights and freedoms, isn’t a sign of weakness in a counter-terrorism response,” commissioner Lorraine Finlay said.

“It’s a clear indication of the strength of our democracy and our values as a nation.”

She said restricting the liberty of offenders who had already served their sentence should be subject to periodic reviews.

The commissioner also raised concerns about the reliability of experts predicting the likelihood of future actions.

“There are real concerns from the commission’s perspective about the reliability of the tools that are currently used to predict the risk of future terrorist activity,” Ms Finlay said.

But Ms Finlay proposed the “control order” regime should ideally be repealed given the implementation of “extended supervision orders”, which are more geared to the relative risk of a released offender.

The Independent National Security Legislation Monitor is examining whether the power is proportionate to the national security threat, meets Australia’s human rights obligations and provides adequate procedural fairness and safeguards.

INSLM head Grant Donaldson says the use of experts is inherently controversial.

“It is controversial simply because what is required is for relevant experts to assist the court by assessing the risk of a defendant committing an offence in the future,” he said.

“That is an unusual and difficult thing and it is inevitably problematic.”

The commission’s deputy general counsel says offenders should not be detained following their sentence if the risk of reoffending is slim.

Graeme Edgerton argued courts in NSW and Victoria had interpreted the current test as fulfilled if there is a slim possibility of offending but it still provides unacceptable risk “if the potential consequences are very grave”.

“We say that it should not only ‘unacceptable’, but also ‘probable’,” he said.

“In terms of probability, we don’t say that should be more likely than not, but there should be some element in there that means that very unlikely occurrences aren’t the basis for holding someone in detention as well.”

Mr Donaldson also attempted to separate extremist ideology and violence.

“We are seeking to protect the community from extremist violence,” he said.

“The key word perhaps in that is ‘violence’. People can have extremist ideologies – that doesn’t necessarily manifest itself into a risk of extremist violence.”

Two continuing detention orders have been made before the supreme courts of NSW and Victoria but no extended supervision orders have been directed by the courts to date.

Division 105A of the Commonwealth Criminal Code sets up a scheme for the continuing detention of “terrorist offenders”, where a court is satisfied that a person poses an unacceptable risk of committing a serious terrorism offence if released into the community at the end of their custodial sentence.

At the time of its introduction in 2016, then attorney-general George Brandis said there were some circumstances where – even with a control order in place – the risk an offender presented to the community was too great for them to be released from prison.

The hearing will run until Thursday.