The worm, thought to be the first to have infected the iPhone, only affects phones that have been cracked - or jail-broken - to let users install applications not approved by manufacturer Apple.

iPhones used with an authorised SIM are not at risk.

"When people jail-break their phone, it allows them to install a service on their phone called SSH," Mr Towns told the ABC.

"Generally you should always change your password after setting up on the iPhone as all iPhones use the same password.

"The virus itself is not malicious and is not out to hurt people. It's just poking fun and hopefully waking people up a little."

He warned that a more malicious worm could have "done anything - read your SMSes, go through your emails, view your contacts, photos - anything".

"I really am sorry to anyone that I have angered, this was meant to be harmless and a bit of a wake-up message," he said.

Towns revealed himself as the worm's author on Twitter under the name Ikeeex, and later seemed surprised by the amount of attention his worm was creating.

"WOW the whole iPhone worm thing is has picked up alot.. its everywhere...," he wrote.