DJs Mel Greig and Michael Christian rang the London hospital treating the Duchess of Cambridge for morning sickness in December 2012, pretending to be the Queen and Prince Charles.
The nurse who took the call later took her own life and there was a storm of publicity over the fact the presenters had obtained personal details about the Duchess of Cambridge.
The Australian Communications and Media Authority (ACMA) ruled the station had breached the law by broadcasting the call without the consent of the other party.
It considered the station had breached New South Wales surveillance laws with the prank call.
The radio station then successfully took legal action against the ACMA in the Federal Court, which found the authority had no power to determine matters of a criminal nature.
But this morning the High Court overturned that decision, finding the media watchdog does have the power to rule if a criminal offence has been committed.
It found the ACMA did have power to make an “administrative determination” that the station had committed a criminal offence, as a preliminary to taking enforcement action under the Broadcasting Services Act.
The court found that in making the determination, the authority was not exercising judicial power
