Laws usually reserved for terrorists are a step closer for a cohort of just under 150 people released from immigration detention after clearing the Senate.
The government brought in the laws after the High Court ruled the detainees should be released as indefinite detention was illegal.
The opposition has been adding fuel to the political fire, spurred on after three of the released detainees were arrested for other offences.
The latest on Tuesday included registered sex offender Emran Dad who allegedly breached his reporting obligations by contacting a child and not disclosing a social media account.
The 33-year-old was also charged with trespassing and didn't apply for bail when he appeared before the Dandenong Magistrates Court on Tuesday.
Dad had an intellectual disability and may require support but had not been receiving disability services while in detention, his lawyer Bernard Keating said.
Another sex offender has been charged with two counts of indecent assault in South Australia and a third man has also been arrested and charged.
The charged detainees were entitled to the presumption of innocence, Australian Lawyers Alliance spokesman Greg Barns said.
Legislation should have been in the works and ready to roll out to keep the worst offenders behind bars in case the court case was lost, the opposition argues.
But a preventative detention regime couldn't have kept the whole cohort behind bars as the government couldn't out-legislate a High Court ruling, Attorney-General Mark Dreyfus said in a statement tabled in the Senate.
The court made a decision that applied to people held in immigration detention in the same circumstances as the original complainant, NZYQ, and detaining anyone affected by the ruling would be unlawful, he said.
Any delay could open the Commonwealth up to legal action over false imprisonment, the attorney-general said.
The government needed to detail how each case related to the ruling, the reasons why they were released and what countries were approached to resettle them, shadow attorney-general Michaelia Cash said.
Labor minister Murray Watt argued former home affairs minister Peter Dutton's failure to take up resettlement deals or deport the cohort was the reason the people were allowed to linger in detention.
The opposition has been given the chance to review the legal advice the government received from the solicitor-general.
The preventative detention regime will capture people in the cohort who pose a serious risk to the community and enable the government to apply to put them back behind bars even if they've served their prison sentence.
It's unknown exactly how many people will be covered by the new detention regime but Mr Watt previously suggested it would only extend to a small number of people.
The preventative detention laws will allow the released detainees to be put back behind bars if a court is satisfied there's a high chance they pose "an unacceptable risk of committing a serious violent or sexual offence".
It would also be a criminal offence for people who have been convicted of serious or violent sexual offences to go near a school or contact their victim or their victim's family.
The maximum length of the order is three years and the minister will need to reapply to the court for a review every year.
There is also mandatory jail time of a year and a maximum of five behind bars if a released detainee breaches an enhanced supervision order that applies to them.
The Greens argue the laws are overreach and create a two-tiered justice system as criminals are released every day.
Labor had capitulated to the coalition to avoid a political fight over national security, Greens senator David Shoebridge said.
"If you have to put a couple of people in jail for the rest of their lives even though there's no evidence of future offending ... Labor are willing to pay that price," he said, pointing to problems with the tools used to assess the risk a person poses.
The amended legislation is set to be ticked off by the lower house on Thursday.
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