Former prime minister and United Nations leadership aspirant Kevin Rudd has blasted world powers over "a possible lost opportunity" in curbing North Korea's nuclear weapons program.
Mr Rudd's remarks, which followed the suspected fourth nuclear test by the rogue regime this week, can be read as a veiled swipe at Beijing but also Washington, which has put North Korea on the back-burner as a nuclear proliferation issue.
North Korea: how big was the test?
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North Korea: how big was the test?
Not all nuclear tests are equal. Here are the numbers on North Korea's purported test on Wednesday.
The former PM, who is believed to be campaigning to become UN secretary-general, said the international community should have used the nuclear deal struck with Iran last July as a springboard for fresh talks with Pyongyang.
He said the dynastic regime of which 32-year-old Kim Jong-un is the third generation was primarily concerned with its own survival and was "wrongly" calculating that it needed a nuclear deterrent to ensure this.
A revival of six-nation diplomatic talks, which Pyongyang abandoned in 2009, was needed to persuade the regime that its survival was possible without a nuclear program.
"After the conclusion of the Iranian nuclear negotiations almost six months ago, I stated it was critical to move immediately onto Pyongyang with a view to open negotiations on the possible delivery of such a long-term guarantee for the regime," he said.
"I fully accept, and have direct experience of, how difficult the regime is to negotiate with. But I am concerned about a possible lost opportunity over the last six months."
His comments came as the UN Security Council condemned the test and pledged to "begin to work immediately" to rein in North Korea following a two-hour crisis meeting.
US officials expressed doubt that the nuclear test was indeed a powerful hydrogen bomb as claimed. This would represent a major technological leap for North Korea and a more worrisome development for the world.
Foreign Affairs Minister Julie Bishop singled out China as critical to reining in Pyongyang given its influence over, and continued economic engagement with, the hermit nation.
"The key to sanctions having an impact is to ensure that countries do not trade with North Korea and so the key, of course, will be China and I believe that China is as frustrated as the rest of the international community by North Korea's most recent behaviour," she said.
Experts agree China, as Pyongyang's only major ally, is the key. But criticism of the Obama administration's approach of "strategic patience" – waiting Pyongyang out – has intensified in the wake of the latest test, with some analysts saying the White House should put more pressure on Beijing to tame its difficult neighbour.
Mr Rudd, now president of the Asia Society Policy Institute in New York, said there was still an opportunity for confidential talks with Pyongyang "to seek to find a way through".
The UN could be a "bridge-builder at this difficult time".
In the meantime, military options became "uglier and uglier", he said. And while there were many security challenges, "the sheer physical dimension of the North Korean nuclear threat should place it at the centre of Australian, regional and global diplomacy and security policy action".