World leaders, including Barack Obama and Vladimir Putin, had their personal details accidentally shared before last year's G20 summit in Brisbane.
But Australia's immigration department determined it was not necessary to notify the presidents, prime ministers and other representatives of the privacy breach.
Passport numbers, visa details and dates of birth of leaders attending the Brisbane summit last November were accidentally sent by a department employee to a member of the Asian Cup Local Organising Committee.
An email from the department to the privacy commissioner, obtained under freedom of information by The Guardian, reveals the breach was reported less than 10 minutes after the email was sent.
The receiver of the email informed the department he had deleted it and there was no other copy.
"The Asian Cup Local Organising Committee do not believe the email to be accessible, recoverable or stored anywhere else in their system," the department's email states.
The director of the department's visa services division sought urgent advice but stated because the risks of the breach were considered very low he did not believe it was necessary to notify the leaders.
"Given the steps taken to contain the breach outlined above, it is unlikely that the information is in the public domain," the email says.
The absence of other personal data, like addresses or contact details, limited the potential risk of the breach, it said.
The email labels it an "isolated example of human error".
It is not clear if the leaders were eventually notified of the breach.
The offices of Australian Immigration Minister Peter Dutton and Scott Morrison, who was responsible for the portfolio at the time, have been contacted for comment.