Labor leader Bill Shorten has accused Prime Minister Malcolm Turnbull of treating Kevin Rudd in a "shabby fashion" for "petty politics" after he refused to endorse him for the United Nations top job.

Australia won't be nominating Rudd for secretary-general of the UN even though he claims Turnbull had told him Australia would be "mad" not to support him.

Shorten, the opposition leader, echoed a comment by his senior minister, Anthony Albanese, labelling Turnbull's actions as "pathetic".

"Malcolm Turnbull's actions are pathetic. "They're disappointing."


Foreign Minister Julie Bishop and Attorney-General George Brandis are understood to have supported Rudd's nomination.

It is possible Australia could back former New Zealand prime minister Helen Clark for the UN role.