A fresh drive to declare nuclear weapons illegal is gathering international momentum ahead of a historic visit by US President Barack Obama to Hiroshima on Friday.
But Australia is part of the "weasel group" of countries opposed to a ban - a stance Indonesia's former foreign minister has warned undermines the chances for nuclear disarmament. 
Mr Obama's visit to Hiroshima will be the first for a serving US president. He has ruled out any official apology, but anti-nuclear campaigners, survivors of the 1945 bombing and a growing number of nations are pushing for a new global treaty that would outlaw nuclear weapons' very existence - with negotiations potentially to begin as early as next year.
At a United Nations meeting in Geneva this month, Indonesia joined Malaysia, Mexico and Brazil in a group calling for a summit in 2017 to begin negotiations on a treaty to ban nuclear weapons - similar to existing prohibitions on chemical and biological weapons.
Australia is prominent among a group of countries that do not own nuclear weapons but see the bomb as central to security.
Japan's government also opposes making nuclear weapons illegal, as does South Korea and most NATO members.
Tilman Ruff, a University of Melbourne professor and founding chair of the International Campaign to Abolish Nuclear Weapons, attended the Geneva talks and said the "weasel" label started as a joke among activists but had been adopted by diplomats.
Indonesia's former foreign minister Marty Natalegawa told Fairfax Media such support of nuclear weapons only served to undermine long-standing calls by the same countries for disarmament.
"Even a discussion on a treaty to ban nuclear weapon, setting aside for a moment its actual achievement, would I believe help create positive dynamics and norms that help delegitimise nuclear weapons," he said.
Many of the dwindling group of Japanese survivors have set aside demands for an apology and instead want to see the world rid of nuclear weapons.
The ALP has said it "firmly supports" negotiations of a global treaty. The Greens also support a ban. But the Coalition has dismissed a ban as emotionally appealing but impractical.
Mr Obama won the Nobel Peace Prize in 2009 in part for promoting a world without nuclear weapons, but the US and other countries with nuclear arsenals are fiercely opposed to a ban.
Akira Kawasaki, from the Japanese anti-nuclear group Peace Boat, said Mr Obama's call for a nuclear weapons-free world was deceptive without support for a ban. "Visiting Hiroshima is good indeed, but is not enough. The US should join the talk, and Japan should shift its position to support a ban," Mr Kawasaki said.
Australia's diplomats at the Geneva meeting called for "a practical way forward".
The UN will decide in   September whether to pursue the ban.