Prime Minister Malcolm Turnbull has criticised Kevin Rudd for releasing private correspondence relating to the former prime minister's attempt to become secretary-general of the United Nations.
Mr Rudd released the letters on Friday night, after Mr Turnbull revealed he had decided not to nominate him for the role as the world's top-ranking diplomat.
In the three letters, dated earlier this year, Mr Rudd wrote that Mr Turnbull had previously told him he would support his bid.
"They were all confidential discussions, they were all private conversations," Mr Turnbull said on Monday.
"It says a lot about Mr Rudd that quite some time after the event he would seek to present an account of them in correspondence he would write to me with the clear intention of subsequently releasing it."
In one letter, dated May 1, Mr Rudd wrote to Mr Turnbull:
"You in fact sent me a message on your preferred Wickr system where you stated that you and the FM (Foreign Minister) were 'as one' in your support for my candidature."
"We continued this discussion further on Wednesday 23 December in your Sydney office. Once again you stated your support for my candidature.
"You added that when the time came to lodge my nomination, you now wanted to take it to Cabinet to avoid the perception of a 'captain's pick'.
"You also said to me that the Cabinet process would not change the outcome."