Acting Immigration Minister Alan Tudge has launched an appeal of a Federal Court judgement that accused him of engaging in criminal conduct by refusing to free an asylum seeker.
Mr Tudge received the scathing ruling after denying an Afghan asylum seeker freedom because he disagreed with the tribunal that ordered his release.
In a judgement last month, Justice Geoffrey Flick warned Mr Tudge placed himself above the law and "engaged in conduct which can only be described as criminal".
Australian Government Solicitor Michael Kingston confirmed the Commonwealth on Wednesday lodged an appeal of the court's decision.
"Part of that is based on an alleged lack of procedural fairness by the court in relation to some of the reasons given for the court withholding the relief," he told a Senate estimates hearing.
"And the court forming those conclusions on either a lack of evidence or a mistake as to the facts."
The case centred on a 34-year-old asylum seeker, referred to as PDWL, who applied for a protection visa in 2016.
The asylum seeker is also suing the federal government for false imprisonment after being kept behind bars despite being awarded a protection visa.
The minister denied the visa in 2019 on the grounds the man was convicted of a criminal offence in 2018.
But in March the Administrative Appeals Tribunal reversed the decision, on the basis that PDWL was not a risk to the community.
The minister immediately appealed the decision and refused to release the refugee from immigration detention, despite the tribunal decision.
But he was released five days later following an earlier Federal Court ruling.
Mr Tudge has previously railed against suggestions of wrongdoing.
"I strongly reject those assertions in commentary. They were comments by a particular judge which I strongly reject," he said earlier in the month.
In his judgement, Justice Flick found the minister was not entitled to keep PDWL in detention merely because he had filed an appeal and no "real explanation" had been provided.
"He has intentionally and without lawful authority been responsible for depriving a person of his liberty," Justice Flick said.
Australian Associated Press