Australian Prime Minister Anthony Albanese said he would back plans to remove Andrew Mountbatten-Windsor from the line of succession to the British throne in a letter he sent to UK Prime Minister Keir Starmer's office.
The BBC has shared a picture of the latter from the Australian prime minister to his British counter part, on their social media accounts.
In the letter, Albanese told Starmer that in light of the recent events, his government would agree to any proposal to remove Charles' younger brother from the line of succession.
"I agree with His Majesty that the law must now take its full course and there must be a full, fair and proper investigation," his letter said. "These are grave allegations and Australians take them seriously."
The last time changes were made to the line of succession came in 2013, when a law was passed to end a 300-year-old system that gave precedence to male heirs.
The British government has said any change would follow the completion of a police investigation. Officers are searching Mountbatten-Windsor's former mansion in Windsor as part of an investigation into whether he committed misconduct in a public office during his time as government trade envoy.
Other allegations relating to Epstein are also being considered by various British police forces. Mountbatten-Windsor, who has made no public comment since the mass release of documents by the U.S. government linked to Epstein last month, has always denied any wrongdoing in relation to the late financier.
Last week, a UK official said the British government was considering legislation to ensure that Mountbatten-Windsor, currently eighth in line to the throne, could never be king following his arrest as part of a police investigation into his ties to disgraced U.S. financier and convicted sex offender Jeffrey Epstein.