Prime Minister Malcolm Turnbull is standing by his assertion Kevin Rudd's poor interpersonal skills and temperament made him an unsuitable candidate for the United Nations top job.
"We all know the reason the government didn't nominate him and we should all move on," Mr Turnbull told 3aw radio on Friday.
Mr Turnbull denied he had breached Mr Rudd's trust, saying he had been frank with him at all times that there was never a guaranteed nomination.
Mr Rudd has warned Mr Turnbull the decision to veto his bid will damage the prime minister's international standing.
The former Labor prime minister also told The Australian the decision represented a "monstrous intrusion" of domestic politics into an international issue.
Mr Rudd said he had a "real shot" of winning the UN post.
"It's no small thing when the prime minister of Australia stands up and says that one of his prime ministerial predecessors is unsuitable to be considered as a candidate for UN secretary-general," he said.
"I think, though, in the counsels of the world, that will reflect poorly on him. I think it will."
His campaign for the job was based on assurances from both Mr Turnbull and Foreign Minister Julie Bishop, he added.
Liberal Party frontbencher Christopher Pyne brushed off Mr Rudd's comments, saying the decision was the right one.
"Look, it's all about Kevin, as usual," Mr Pyne told Nine Network on Friday.
"The announcement that we wouldn't nominate him for Secretary-General of the UN has underlined why he was not a suitable candidate because his behaviour has been quite extraordinary."
Mr Rudd said he recognised Mr Turnbull had the right to make such decisions.
"What I don't respect is, having pursued this campaign for United Nations Secretary-General for such a long period of time in absolute good faith, to then see that good faith dishonoured and trust broken," he said.
"It was always assumed in these conversations that the government would support me."
