High Court decision could lead to tens of millions of dollars worth of immigration claims

Safwat Abdel-Hady argues he was falsely imprisoned when he was kept in indefinite immigration detention. (ABC News: Matt Roberts)

Safwat Abdel-Hady, who suffers a condition which carries a high risk of thrombosis preventing him flying, argues he was falsely imprisoned when he was kept in indefinite immigration detention.

The government took the case to the High Court because it wanted the court to find that even if Mr Abdel-Hady had been falsely imprisoned the government should not be liable.

The High Court found the government's case failed at the level of constitutional principle.

There are warnings a High Court ruling allowing a man to sue for false imprisonment over his indefinite immigration detention will lead to more claims running into the tens of millions of dollars.

Safwat Abdel-Hady was placed in immigration detention in 2017 after a criminal conviction.

He argues he was falsely imprisoned when he was kept in indefinite immigration detention, even after the government admitted that from mid-2022 he could not be removed from Australia for health reasons.

Mr Abdel-Hady, who is Austrian, suffers a condition which carries a high risk of thrombosis which prevents him from flying.

A minor High Court correction to a landmark ruling embodies how the recent NZYQ saga has up-ended Australia's immigration detention system and shaken its political and legal institutions.

Today's case only applied to the date from which the government conceded he could not travel, from July 2022 until the High Court ruling in November 2023, and that indefinite immigration detention is illegal where there is no real prospect of removal from Australia becoming practicable in the reasonably foreseeable future.

Those who were released after the ruling have become known as the NZYQ cohort.

Mr Abdel-Hady's case has been in the Federal Court for some time, but was taken to the High Court by the government.

It wanted the court to find that even if Mr Abdel-Hady had been falsely imprisoned the government should not be liable.

The High Court found the government's case, that it and its officers had a defence against liability for false imprisonment under the common law, failed at the level of constitutional principle.

The majority decision said it did not accept that immunity applied in circumstances where the limits of the power of the officers and the government were exceeded.

The court said if it accepted the defence proposed by the Commonwealth it would provide an unsustainable protection to the officers for unlawful acts based on the court's ruling rather than th