An international conference of 132 governments is meeting in Oslo this week to examine the humanitarian impact of nuclear weapons.
Australia Red Cross CEO Robert Tickner has told Radio Australia's Connect Asia program the time has come for governments to take a stand on the issue.
"It's just incredible to my mind that we have a convention around land mines, around cluster munitions - essentially saying that they are no longer weapons of war - but we don't around the issue of nuclear weapons," he said.
"One of the greatest threats to humanity on the planet is the potential use of nuclear weapons.
"They are indiscriminate, they literally obliterate millions of people in one flash, they have the capacity...to destroy not only a whole city, but whole regions, [and to] affect agricultural production and have an impact on climate that can transcend national borders for decades."
The Red Cross says Australia's main political parties have backed the call for a convention.
Last year, US President Barack Obama announced he was pushing for a "world without nuclear weapons" .
Mr Tickner says a convention would be an important first step towards that goal.
"We ought to focus on the humanitarian consequences of the use of nuclear weapons," he said.
"That would essentially mean a convention that would render the use of nuclear weapons illegal under international law.
"It is a challenging issue how the world moves to disarmament, but the first task we think is the de-legitimisation of the use of nuclear weapons."