The Treaty on the Prohibition of Nuclear Weapons is a UN negotiated agreement that the New Zealand Government has already signed. But that doesn't actually mean much. Not yet. Not until Parliament agrees.
That second step (ratification) is now underway. The treaty has been tabled in Parliament and sent to the Foreign Affairs, Defence and Trade Select Committee for its investigation and approval, then it will return to the house for formal ratification.
This is no longer a contentious issue in New Zealand so the outcome is likely not keeping anyone on tenterhooks.
National MP Simon O'Connor, Chair of the Foreign Affairs, Defence and Trade Select Committee, explains that not only does Parliament have to ratify the signing, it often has to go further.
"On some occasions domestic legislation has to be put in place to make that international treaty valid. In other words we have to have a New Zealand piece of law which specifically says we agree with this treaty and we're going to be bound by it."
Sometimes this process is long and involved because Parliament has to devise its own legislation to comply with a treaty. Also on the committee, Green MP Golriz Ghahraman points out that Parliament did exactly that last week when it passed the Brokering (Weapons and Related Items) Controls Act, which also traversed the foreign affairs committee.
"It was exciting for me... to see a treaty come down to that legislative level. And we talked about 'how do we actually give effect to the principles in this treaty? ...How do we effectively control weapons brokering in the New Zealand context? So, what body will oversee that, what standards will we apply...? What weapons do we include?' The mechanics of it become quite important. And we did it. We passed it."
Obviously it's pointless joining an international treaty if you don't give yourself authority to enforce it on your own territory, but Simon O'Connor notes that the nuclear weapon ban one will be easier.
"In this particular case, we don't actually need domestic legislation because we already have some. Because New Zealand's been in the forefront of anti-nuclear activity we already have the... legislation to enable us to accept this treaty."
It's already illegal in New Zealand to manufacture, own, store or use nuclear weapons (even someone else's weapons). This is probably not a surprise to you.
You can read the treaty itself online, as well as the National Interest Analysis prepared by the Ministry of Foreign Affairs and Trade. An analysis is prepared for every treaty under consideration and attempts to tease out the advantages and disadvantages of ratification.
If you want to make a submission on the Treaty you have until Friday June 8th.