Apple devices across Australia were reportedly hacked with hackers claiming $100 ransom.

An Apple iPad owner from Melbourne Australia, veritylikestea first posted about the problem through Apple's support forum.

"i was using my ipad a short while ago when suddenly it locked itself, and was askiwhich I'd never previously set up. I went to check my phone and there was a message on the screen (it's still there) saying that my device(s) had been hacked by 'Oleg Pliss' and he/she/they demanded $100 USD/EUR (sent by paypal to lock404(at)hotmail.com) to return them to me.

I have no idea how this has happened. I am not aware of having been exposed to malware or anything else, although i did recently purchase some new apps - perhaps one of these has something to do with it? I don't know. I am not sure what avenue has been used to reach my devices - I'm about to use my husband's laptop to check through some of my accounts (gmail, etc) and see if there is any clue there," veritylikestea wrote on May 26.

Apparently, a considerable number of Australian with Apple devices are experiencing the same.

"iPad woke me at 4.30am with the message 'Your device has been hacked by Oleg Pliss' and sound -- I thought it was the morning alarm . I then signed in to my powerbook -- but as a guest user -- VERY grateful I did. Message to say I'd been hacked there too, wouldn't let me sign out without erasing all data for that user. As there was nothing but a couple of expendable files on there, I signed out. And the guest user portal has been erased," wrote user deskokat.

Some users said they have been calling Telstra, Vodafone and Optus, and some have been calling Apple repeatedly.

"Vodafone kept saying 'iPhone can't be hacked,' " Shleighbo, wrote in the support forum.

"Rang Telstra and they said it is an Apple issue," georgie81 said.

"The Optus tech support was not helpful," Bettybam posted.

CNET contacted telcos Optus and Vodafone for their statements.

Both Optus and Vodafone said that they have not received an official complaint yet.

"If customers have any questions about their Apple devices, they should speak directly to Apple", Optus spokesperson told CNET.

Vodafone also said "to speak with Apple as they are best placed to offer comment on their services".

Apple and Telstra had yet to comment.

Troy Hunt, an IT security expert told Sydney Morning Herald that hackers were seemingly using password reuse to gain access to Apple devices.

"It's quite possible this is occurring by exploiting password reuse. Regardless of how difficult someone believes a password is to guess, if it's been compromised in another service and exposed in an unencrypted fashion, then it puts every other service where it has been reused at risk. Of course it also suggests that two- factor authentication was likely not used as the password alone wouldn't have granted the attacker access to the iCloud account," Hunt explained.