A YouTube video threatening 2Day FM and its advertisers is being investigated by the police.
The video, purporting to be from the vigilante "hacktivist" group Anonymous, was posted on December 8 by the An-onym Oz account.
It appeared the day after British nurse Jacintha Saldanha apparently took her own life.
She'd answered the prank call made by 2Day FM presenters Mel Greig and Michael Christian, posing as the Queen and Prince Charles, to the London hospital treating the pregnant Duchess of Cambridge.
The video features a character wearing a Guy Fawkes-style mask and making threats against 2Day FM and its advertisers - including hacking their databases.
"We have listened to your excuses,'' the character says via a voice synthesiser.
"We have heard the word 'prank' a million times, we have studied the facts and found you guilty of murder."
The video, which has now been removed from YouTube, goes on to suggest the radio station "makes amends" by firing the presenters who made the prank call and paying for Ms Saldanha's funeral.
It adds: "You have placed your advertisers at risk - their databases, their websites, their online advertising."
A formal complaint has been made to the police and 2Day FM has taken extra precautions to protect both its staff and computer systems in the wake of the video.
A message posted by YouTube said the video was removed because it violated "YouTube's policy on depiction of harmful activities".
Anonymous, a loose collective of cyber activists, has previously claimed responsibility for hacking the Pentagon and the Australian government.
The video's veracity remains unclear, with plenty of debate online as to whether it was posted by a member of Anonymous.
However, a message posted on the anonnews.org website, which is believed to be affiliated with the group, suggests there is no formal membership procedure.
"Anonymous does not have a membership list and you can't really 'join' it either," it reads.
"If you identify with or say you are Anonymous, you are Anonymous."
Comment has been sought from police.