Australia supports a plan to block Andrew Mountbatten-Windsor from ever becoming king after the former prince was arrested over the alleged leaking of secret documents to dead paedophile Jeffrey Epstein.
Prime Minister Anthony Albanese has written to his UK counterpart Keir Starmer to support the push to remove the disgraced former royal from the line of succession to the British and Australian crowns.
"In light of recent events concerning Andrew Mountbatten-Windsor, I am writing to confirm that my government would agree to any proposal to remove him from the line of royal succession,'' Mr Albanese wrote to Mr Starmer.
"I agree with His Majesty that the law must now take its full course and there must be a full, fair and proper investigation.
"These are grave allegations and Australians take them seriously."
Mountbatten-Windsor is eighth in line to the throne, which means he could technically become Australia's head of state.
But such a scenario is unlikely because it would require the death of King Charles, Prince William, Prince Harry and five royal children.
The UK is considering removing Mountbatten-Windsor from its line of succession as a symbolic move after his arrest.
Such a change would likely require legislation in the UK and all other countries which still have the British monarch as their head of state, including Australia.
Mountbatten-Windsor was arrested on his 66th birthday after a trove of emails released in the US suggested he leaked confidential documents to Epstein while serving as the UK's trade envoy.
The former prince has also been dogged by accusations he sexually abused Virginia Roberts Giuffre and other women when they were teenagers - claims he denies.
Mr Albanese has described his arrest as a fall from grace but says he is not planning a referendum for Australia to leave the monarchy and become a republic.Â