Is the NSG a Treaty Based Organisation?

No. The NSG is a voluntary, non-legally binding association of major supplier governments. It was not created by a treaty. The NSG Guidelines set forth conditions of supply to establish a baseline of responsible and safe supply behaviour among suppliers in nuclear and nuclear-related transfers. NSG participants commit to implement the guidelines on a national basis. Taking a supply side approach, the NSG supports international nuclear non-proliferation efforts and in particular Article III.2 of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT).