The world is on the brink of an avalanche in the spread of devastating weaponry, a new global non-proliferation group warned Tuesday, saying that a nuclear incident would dwarf the September 11 attacks.

The Middle East, particularly Iran, is a potential tipping point, according to Gareth Evans, co-chair of the newly formed International Commission on Nuclear Non-proliferation and Disarmament.

Evans, a former Australia foreign minister, said the world had been "sleepwalking" on the issue of atomic weapons for a decade.

"The devastation that could be wreaked by one major nuclear weapons incident alone puts 9/11 and almost everything else (in) to the category of the insignificant," he said, referring to the attacks inflicted on the United States in 2001.

Evans was speaking as the commission, which was first proposed by Australian Prime Minister Kevin Rudd after a visit to the Japanese city of Hiroshima in June, entered the second and final day of its inaugural meeting in Sydney.

The group, chaired by Evans and Japan's former top diplomat Yoriko Kawaguchi, is tasked with reinvigorating the global debate on the spread of nuclear weapons and disarmament.

Evans told reporters there were between 13,000 and 16,000 nuclear warheads actively deployed around the world and that it was "really a bit of a miracle" that a nuclear catastrophe had not occurred during the Cold War or afterwards.

"But unless we energise ourselves, unless we re-invigorate a high level political debate which is then accompanied by effective action, we potentially have very alarming consequences staring us in the face," he said.

"We are on the brink of... an avalanche or a cascade of proliferation unless we are very, very careful indeed and find ways collectively to hold the line."

Evans, Australia's foreign minister from 1988 to 1996, said the world had failed to address the rise of nuclear-armed India and Pakistan and the assumption that Israel also possesses such weapons.

But he pointed to the Middle East as a key area of concern.

"If there is a breakout by Iran, or a perceived breakout by Iran, the Middle East alone is the cockpit in which we can anticipate such a cascade of proliferation by a number of other countries," he said.

A change in leadership in the US, however, may provide a breakthrough in international talks, before comparing possible changes under Republican candidate John McCain and Democratic candidate Barack Obama.

"An Obama administration would, on the face of it... be one that's likely to be more substantially focused on this but even with an McCain administration, it would be an improvement," said Evans. "There's not much to beat frankly."

He said if the US were to sign up to the Comprehensive Test Ban Treaty the implications would be "quite profound" and could lead to China finding itself under "irresistable pressure" to do likewise.

"That in turn would, I think, have ripple effects right throughout the international community," he added.

The commission, whose members include former US secretary of defence William Perry and Norway's former prime minister Gro Harlem Brundtland, is working towards building consensus ahead of a 2010 conference on the 40-year-old Nuclear Non-Proliferation Treaty (NPT).