A decision by Australia's highest court to reinstate a convicted terrorist's citizenship, effectively halting a bid to deport him, is not necessarily bad for national security, two constitutional law experts say.
The High Court struck down a provision in the Australian Citizenship Act allowing a minister to cancel the citizenship, ruling it was invalid as it permitted the minister to punish criminal guilt, which was an "exclusively judicial function".
The Algerian-born convicted terrorist Abdul Nacer Benbrika is expected to be released into the community following the High Court's decision.
Stripping citizenship had a "symbolic attraction" but was a thin shield for national security, legal scholar Rebecca Ananian-Welsh argued.
"When it comes to actually protecting security, the evidence shows that citizenship-stripping comes up short," Associate Professor Ananian-Welsh wrote in The Conversation.
People stripped of their citizenships had gone on to commit terrorist acts overseas, she said, pointing to Australian foreign fighter Khaled Sharrouf.
Cancelling citizenship could also boost propaganda for extremists, especially on the internet.
Instead, people kept in Australia bear the brunt of national security laws, including orders to keep terrorists detained after they serve their sentences if they are a risk to the community, or enhanced surveillance upon their release.
Stripping citizenship isn't proven to be an effective means of protecting the community and the world at large from terrorism, constitutional lawyer George Williams told AAP.
This was due to the potential inability of other nations to deal with the threat posed by the terrorists or the possibility of tit-for-tat retaliation by stripping the citizenship of dual Australians and deporting them, he said.
Professor Williams also took aim at how the laws were drafted by the former coalition government, saying the High Court ruling was straightforward and unsurprising and a vindication of the separation of powers in Australia.
"It applies the basic principle that it is for the courts and not politicians to judge guilt and impose criminal punishment," he said.
"The law infringed this by enabling a minister to impose an additional punishment of citizenship revocation."
Acting opposition leader Sussan Ley said the coalition acted on the best advice when drafting the laws while in government.
She called for Labor to introduce legislation to ensure Benrika's citizenship was not restored.
"Mr Benbrika is a convicted terrorist, and remember, he did plan to conduct violent attacks against Australians on Australian soil," she told ABC Radio.
The High Court's ruling required careful consideration and an appropriate government response, Immigration Minister Andrew Giles said.
"It's critically important that we consider the judgment in detail," he told ABC TV.
Home Affairs Minister Clare O'Neil has flagged new laws to strip dual citizens found to engage in terrorist acts but said she wanted to make sure they were robust enough to withstand a High Court challenge.
Benbrika is set to be freed after the Commonwealth and his lawyers agreed to drop a continuing detention order, which allows for a person to be kept in prison after serving their sentence if they pose an unacceptable risk.
A report buried by the home affairs department found the method used to determine the future risk an offender posed - which then underpinned the assessment to keep them behind bars - was no more accurate than flipping a coin.
The report was seized upon by Benbrika's lawyers when it came to light to argue the validity of his initial three-year detention order imposed in 2020.
The Commonwealth agreed to drop the detention order in favour of a supervision order, which allows for 24-hour monitoring including scrutiny of telephone and online communications, friendships and movements.
Benbrika will be freed once a Victorian court determines the parameters of the supervision order.
The terrorist's detention order expires on December 23.
