The United States and Australia schemed unsuccessfully in 2005 to block Mohamed ElBaradei's election to a third term as head of the International Atomic Energy Agency, a newly leaked US diplomatic cable shows.

Both countries were unhappy with ElBaradei's "unhelpful" response to Iran's nuclear program, but the bid to prevent his re-election to the nuclear regulatory agency's leadership ultimately failed for lack of international support.

The February 18, 2005 State Department cable released by WikiLeaks Tuesday opens a window into the effort, describing a lunch conversation between Australian officials and a US special envoy for nuclear non-proliferation, Jackie Sanders.

The cable spotlights US and Australian concerns over the Egyptian diplomat's interpretation that Iran had a "right" to civilian nuclear power, and his reluctance to declare Iran in non-compliance with the nuclear Non-Proliferation Treaty.

Australian officials said there weren't the 12 votes on the IAEA board of governors needed to deny ElBaradei reelection, "but that did not stop them from speculating on ways to try to prevent his re-election," said the cable.

John Carlson, then head of Australia's nuclear safeguards agency and one of the officials at the lunch, said Canberra strongly supported limiting IAEA chiefs to two terms, according to the cable.

"Carlson commented that ElBaradei was a very bad manager and morale throughout the IAEA staff was 'appalling,'" the cable said.

The problem, however, was that no other candidate would step forward to challenge ElBaradei as long as the Egyptian diplomat was in the running, and not enough members of the board of governors would vote against him, Carlson said.

A US official at the lunch asked whether an Australian candidate could be put up against ElBaradei, but Carlson said that could work only if ElBaradei first withdrew from the running.

"Sanders responded that there had been a time in the past when the numbers of ElBaradei non-supporters were there, and the issue was not over yet," the cable said.

"Carlson observed that in a secret ballot, anything could happen. It might be useful to put the word out in Vienna that ElBaradei could fail," it said.

The cable also included an informal document forwarded by Carlson, who had not yet cleared it with his government, entitled "The case against ElBaradei."

The brief argues that ElBaradei's reports to the IAEA's board of governor appeared to have been made with the object of stalling a finding that Iran's nuclear program was in non-compliance with the NPT.

"Iran's success in avoiding a non-compliance finding has emboldened it to press on with the nuclear program," it said.

"Meanwhile, the handling of the non-compliance issue has seriously damaged the integrity and credibility of the IAEA's processes. A change is needed in the IAEA leadership, to return the Agency to its technical function," the document said.

But ElBaradei survived the challenge, and went on to serve until 2009.