Detectives who investigated the prank call to the hospital where Kate Middleton was treated have passed a file to the Australian police.
The hoax call from two Australian DJs led to a nurse involved in the incident at the King Edward VII hospital committing suicide.
Mother-of-two Jacintha Saldanha, 46, was on reception duty at the London hospital where the duchess was being treated for morning sickness.
Radio presenters Mel Greig and Michael Christian rang in December, pretending to be the Queen and Prince Charles, and asking for a condition report.
Mrs Saldanha believed the two DJs and put them through to a nurse helping treat the duchess for morning sickness who also gave details of her condition.
The nurse was found hanged three days later.
British prosecutors have already said that no legal action will be taken in this country over the call, but yesterday the Metropolitan Police sent the information to the Australian Federal Police and New South Wales police.
A spokesman said: "On 9 July the Metropolitan Police Service (MPS) passed a file to the Australian Federal Police and New South Wales police in relation to a hoax call made to the King Edward VII Hospital on December 4 2012.
"The MPS has requested that consideration is given as to whether any offences were committed under Australian legislation.
"Following an investigation by the MPS into this matter a file was passed to the Crown Prosecution Service (CPS) in December 2012. On February 1 2013 the CPS advised no charges would be brought in the United Kingdom."
Earlier it was reported that one of the DJs who made the call is taking legal action against the radio station.
Ms Greig is accusing her employer Southern Cross Austereo of failing to provide a safe workplace at 2Day FM radio station, the Melbourne Age has reported.
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Ms Greig's lawyer, Steven Lewis of Slater & Gordon, told Fairfax Media: "I can confirm that a general protections application has been filed with Fair Work Australia on behalf of Mel Greig against Southern Cross Austereo.'
The application alleges Southern Cross Austereo failed to maintain a safe workplace in relation to the hoax phone call incident.
Ms Greig has not returned to work since the incident but Mr Christian was controversially awarded the internal "Next Top Jock" competition for DJs at his employer which aimed to find the "best in the land".
Ms Greig's legal action comes as Southern Cross Austereo awaits a decision from the Federal Court about the authority of the broadcasting watchdog, the newspaper reported.
MP Keith Vaz, who has offered support to Mrs Saldanha's family, said: "The decision by Ms Greig to sue the radio station is brave, although it comes as no surprise. Ultimately the radio station made the decision to broadcast the hoax call and must bear responsibility for the tragic death of Jacintha.
"It seems that the DJs and radio station are now turning on each other. I hope Ms Greig will clarify her position at the inquest in September.
"This has been an unbearable time for the family. They are very much awaiting the results of the postponed inquest. They simply just want to get on with their lives. "
