The Geneva-based organisation, recognised by the Nobel committee for its decade-long campaign, was a key player in the adoption of a treaty symbolically banning nuclear weapons, signed by 122 countries at the UN in July.

NATO, which has three of the world's nuclear powers in its ranks, strongly criticised the treaty, saying it risked undermining the international response to North Korea's atomic weapons programme.

Jens Stoltenberg, the alliance's secretary-general, welcomed "the attention given to the issue" of disarmament by the Nobel Committee and said NATO was committed to creating conditions for a world without nuclear weapons.

But he restated his criticism of the nuclear ban treaty -- which was shunned by all nuclear powers -- saying it put years of progress on non-proliferation at risk.

"What we need is verifiable and balanced reduction of nuclear weapons. The Nuclear Non-Proliferation Treaty, which all NATO Allies have signed, remains the cornerstone of international efforts to do so," he said in a statement, adding that NATO would remain a nuclear alliance as long as nuclear weapons existed.

"NATO regrets that the conditions for achieving nuclear disarmament are not favourable today, but efforts towards disarmament must take into account the realities of current security environment."

Disarmament campaigners hailed the July treaty as an important step but most NATO members boycotted the talks to prepare the text, as did Japan -- the only country to have suffered nuclear attacks, in 1945.

Nuclear powers argue their arsenals serve as a deterrent and say they remain committed to the gradual approach to disarmament outlined in the nuclear Non-Proliferation Treaty.