Australia may begin releasing scores of refugees in immigration detention within days following a landmark High Court ruling.

A majority of the High Court on Wednesday found the indefinite detention was unlawful and overturned a 20-year-old precedent.

At least 92 detainees who can’t return to their original country might be freed and another 340 in long-term detention could join them, the court was told.

Immigration Minister Andrew Giles said the government was carefully considering the implications of the judgment and would continue to work with authorities to ensure community safety.

“Other impacted individuals will be released and any visas granted to those individuals will be subject to appropriate conditions,” he said on Friday.

The plaintiff, a Rohingya man from Myanmar known as NZYQ, has been released.

He faced the prospect of life in detention as no country would resettle him because he raped a 10-year-old child.

Opposition home affairs spokesman James Paterson said he had no confidence in the government’s assurances.

“They haven’t said what crimes these people have committed … provided no detail or no transparency to the Australian people,” he said in Canberra.

Senator Paterson pressed the government during Question Time, about whether the 92 people would be released before or after the court’s reasoning behind the judgment was handed down.

He asked how many of those people have been assessed by a court for their risk of reoffending, as some had been convicted of sexual and violent offences.

Cabinet minister Murray Watt told the Senate that all issues were being worked through, and the government considered community safety “paramount”.

“We are considering the implications of the High Court judgment carefully and we will continue to work with authorities to ensure that community safety is upheld,” he told parliament on Friday.

“The government will use all available powers to keep the community safe and will consider all legislative and regulatory options.”

Deputy Prime Minister Richard Marles said the Albanese government acknowledged people had concerns.

“The government will do everything within its power to ensure that this release happens under the strictest possible conditions,” he said.

“We will be assessing our options once the full decision of the High Court is made public and we can go through the reasoning of the court decision to work out what our next steps are, but we will ensure that those steps are absolutely legally robust.”

The Asylum Seeker Resource Centre said Australia held immigration detainees for an average of 708 days and 124 people had been detained for more than five years.

– AAP