Freed detainee accused of horrific grandmother assault

Arrest of a recently freed detainee from immigration detention
A former immigration detainee is accused of bashing a Perth grandmother unconscious. -AAP Image

A federal minister has admitted the government is "deeply concerned" after a Perth grandmother was assaulted, allegedly by a recently freed immigration detainee during a violent home invasion.

The man was one of three people arrested over the assault and robbery of 73-year-old Ninette Simmons earlier in April.

Western Australian police allege the trio assaulted Ms Simmons' husband Philip, 76, and tied his hands behind his back, before stealing $200,000 worth of jewellery.

The three offenders gained access to the couple's home by posing as police officers.

The former detainee was one of 154 men released from immigration detention in November after the High Court ruled indefinite detention was unlawful.

The men are accused of impersonating police to gain access to the couple's home. (Supplied/AAP PHOTOS)

Industry Minister Ed Husic says the situation is concerning.

"We are deeply concerned about what we have seen, we have had to respond to a court decision that required the release of those detainees and put in place measures to be able to protect the Australian public as much as we possibly can," he told ABC TV on Tuesday.

"Clearly, we will have more to say about this, but feel deeply for Ninette, for what they've gone through, and we will take every step required of us."

Ed Husic says the government is deeply concerned about the violent attack on the couple. (Mick Tsikas/AAP PHOTOS)

Opposition Leader Peter Dutton has called for Immigration Minister Andrew Giles and Home Affairs Minister Clare O'Neil for an explanation over the incident.

"Sadly, it's victims like we've seen in Perth, and I think like we'll see across the country, who are paying the price for the incompetence of the Albanese government and the two ministers ... are missing in action," he told Nine's Today program.

"There needs to be transparency, because from day one, the government shrouded everything in secrecy, and if they've got nothing to hide, then they should be up front and open with the Australian people."

While the government tried to ram laws through parliament in March that would impose mandatory minimum one-year prison sentences for immigration detainees who don't co-operate with deportation attempts, the proposal was delayed by the opposition and crossbench.

Mr Dutton denied opposing the laws for political gain.

"We demanded that the government strengthen the legislation often, which is what they ended up doing, because what they put forward originally was so weak," he said.

WA Police Detective Inspector Gary Butler said the assault had caused enormous stress and anxiety for the couple.

"Life will never be the same for them. And our work doesn't stop here as we just continue to seek justice for this horrific offending," he said.

"It's still part of our investigation to try and establish how Ninette and Philip became a target. We're comfortable that here's no ongoing threat to members of the community."