Those sensors have been cryptographically secured by Apple during the original process of manufacture and cannot be reset by third-party repairers. Error 53 epicentre: A magnified view of the home button and home button cable on an iPhone 6. Credit:iFixit When the user tries to upgrade the iPhone or iPad to an updated version of the operating system by syncing the device to iTunes, a dialogue box will appear on the screen saying: "The iPhone could not be restored. An unknown error occurred (53)." At that point, the device will shut down, cease to operate and all the data that is not backed up will be irretrievably lost. Independent repairers say there is no known way to restore a device that has been "bricked" with the Error 53 malfunction. A spokesman for the ACCC said it would write to Apple "urgently seeking" a response to concerns raised by consumers about the malfunction.

"We are currently considering whether the reports are likely to raise concerns under the Competition and Consumer Act," a statement provided by the commission reads. "The iPhone could not be restored": Apple's "error 53" alert. "In particular the ACCC is examining whether this practice contravenes the consumer guarantee and false and misleading representations provisions of the ACL [Australian Consumer Law]. The ACCC would also be concerned about any practices which restrict competition, including through access to parts or data." Apple has responded to similar concerns raised overseas, saying Error 53 is the result of security checks intended to protect its customers. "This security measure is necessary to protect your device and prevent a fraudulent Touch ID sensor from being used," the company said.

To date, the error has largely been reported by owners of the 2014 models of the iPhone 6 and 6 Plus. The same fingerprint security technology is used on the iPhone 5s and the latest iPhone 6s and 6s Plus models. The Touch ID technology is also used on the iPad Pro, the iPad Air 2 and the iPad mini 4. The growth in the popularity of Apple's hand-held devices over the past decade has led to the emergence of a burgeoning third-party repair business. According to Apple, more than 1 billion of its devices are now in use worldwide. While Apple has a network of stores and authorised repairers, work done by these is generally priced at a premium. And the stores are usually located only in the popular shopping precincts of big cities. Shaun Moffatt, the owner of the Sydney mobile phone repairer Fone Fix, is worried that the adverse publicity around Error 53 might scare customers away.

He says he has fielded many calls recently from people asking if it's still safe to bring their iPhones in to be repaired by his technicians. Even though 99 per cent of repairs at his two shops were for cracked screens, he feels the hysteria around the issue is "bound to have an effect on us". "It's just gone crazy," he said. Patrick Lee, a director of phone repair company iExperts, is less concerned at the impact on his chain of stores because, depending on the nature of the repair, he says his company has a possible work around - one that necessitates sending the damaged phone to China. And he does not subscribe to the view that Apple is deliberately trying to assert a monopoly over the iPhone and iPad repair business.

"I do accept their explanation about the security factor," he said. Apple did not respond to questions raised in the ACCC statement, but has provided links to the ID Touch and Error 53 support pages on its website.