Kevin Rudd has described Malcolm Turnbull as a “brick wall” in what was intended as a private address to a Young Labor gathering in Brisbane.

Mr Rudd was captured on video speaking to the young Labor party members after the prime minister on Friday opted not to support his hopes to nominate for the job as United Nations Secretary General.

“I’ve got a very dark, deep secret for you, sometimes it’ll turn to s***, and sometimes it won’t turn out perfectly,” Mr Rudd said in the video uploaded to Facebook by ALP member Pat O’Neill, who recently ran unsuccessfully for the federal seat of Brisbane.

“I’ve had a modest experience of that, just a little bit, including (Friday).”

He said it was part of the “collective scar tissue of life”.

Mr Rudd told the youngsters it was important to be confident in their social values and hang on to them when thrown into the “brick walls of life”.

“One of those other brick walls presented itself in the form of Malcolm Turnbull,” he told the group.

Mr Rudd publicly released his letters to Mr Turnbull about the nomination, hours after his rejection.

Mr Turnbull fired back, saying the move says a lot about Mr Rudd.

He also said Mr Rudd had released accounts of conversations and meetings that were at odds with his recollection and in one case “absolutely untrue”.