Strict laws that would keep prisoners behind bars if deemed a risk of committing a terrorist offence - even if they haven't before - have passed NSW parliament.
The government bill, which passed the upper house on Wednesday, allows the attorney-general to apply to the Supreme Court to have a prisoner's sentence extended for up to three years if they're considered a risk.
Rolling extensions could continue, effectively, for the rest of the offender's life.
Greens MP David Shoebridge said the legislation, which was designed to keep people in jail, "erodes one of the core principles of our justice system".
"You go to jail if you are planning to commit or committed a crime and are found guilty by a court - not because authorities fear you will in the future," Mr Shoebridge said in a statement.
"The Liberal's High-Risk Offenders Bill does the work of the terrorists for them."
An offender would undergo a rehabilitation review during their time in prison or under supervision, followed by a medical assessment.
They could then be subject to continued detention or extended supervision.
A person imprisoned for a non-terror related crime but radicalised in jail could be subject to the three-year jail extension under the proposed laws.
Mr Shoebridge said the government was casting its net too wide.
"This bill is aimed at keeping people in jail who were not originally sentenced for terrorism because they may have been radicalised in prison," he said.
Nationals MP Trevor Khan acknowledged the legislation was tough but said the government must make difficult decisions to keep Australians safe.
"Yeah, these are compromises that we are making but if we are to keep the people of Australia, the people of NSW safe, then compromises we make."
"We are in difficult circumstances and that requires us to make difficult decisions."
Last week, NSW Attorney-General Mark Speakman said he made "no apologies" for the tough laws.
"There's no doubt that laws to keep offenders behind bars after they've completed sentences are tough laws," he told parliament.
"The NSW government makes no apologies for this."
However NSW Bar Association president Arthur Moses said the association opposed any legislation which kept people in jail based on "speculation".
"The threat of terrorism is serious and cannot be underestimated," Mr Moses told AAP in a statement.
"However the way to keep the community safe is not to take away the rights of people but to provide police with proper resources to properly investigate matters, charge suspects and bring people before the courts to be dealt with according to law."
