MALCOLM Turnbull has revealed that he will ring Kevin Rudd personally about his potential nomination to lead the United Nations.
When asked about his decision, Mr Turnbull told reporters in Canberra: "I owe Mr Rudd a telephone call before I say anything more about it publicly".
Labor and the Greens had called on the government to support Mr Rudd, citing support for former Australian prime ministers including Malcolm Fraser, in bids for worldwide roles.
There are already 12 in the field, including former New Zealand Labour prime minister Helen Clark, who has the full backing of that country's conservative government, and former Portuguese prime minister Antonio Guterres, who is the early frontrunner.
Mr Rudd wasn't on the list because he hadn't been nominated, but there's no deadline for that.
Any further delay could have potentially thrown Rudd's bid into doubt as consideration of candidates by UN member nations gets under way next month. "Thank you very much", Mr Turnbull said.
Speaking on Sydney radio 2GB on Tuesday, Mr Morrison said Labor had been unwilling to support Howard-government treasurer Peter Costello as head of the International Monetary Fund in 2011.
Morrison, Dutton, Industry Minister Greg Hunt and several government backbench MPs have publicly questioned his merit and suitability to be secretary-general.
The Australian quoted a Liberal MP, who said: "It will make people very angry if Malcolm Turnbull can't find a place for former Liberal prime minister Tony Abbott on his frontbench but can back a former Labor prime minister for the top job at the United Nations".
"Any cursory glance at Mr Rudd's temperament and capacity would show that Mr Rudd is poorly qualified for this role", Senator Abetz said in a statement.
A year before, when the two were still prime ministers, a mischievous official briefing note prepared by Australian diplomats ahead of Mr Rudd's visit to New Zealand described Ms Clark as a left-wing control freak - which she later dismissed as a "hoot".
Plibersek said Rudd was a distinguished former prime minister, a very successful foreign minister, diplomat with decades of experience, and is an acknowledged expert on China.
"They said he was a narcissistic psychopath which is pretty rough".
The next secretary-general will take office on January 1.
After weeks of speculation and resistance from senior Coalition ministers, Prime Minister Malcolm Turnbull said on Thursday he needed to call the former Labor leader before discussing the decision.