nickreno: I phoned Weber NZ - friendly, but they advised the bbq would need to be certified for use in NZ by a gas fittter, who could then order replacement parts.

I instead purchased a 'qcc to 1" unef' gas pipe from Mitre10, which was both cheap ($40 after price match) and fits. The USA connection style had many names but the wikipedia article and above responses were very helpful - thank you

The product i purchased was https://www.gasmate.co.nz/products/hose-adaptor-qcc-1-unef-male-1m-hp-hose

Does that mean it's certified? You might want to have a chat with your insurance company, they may exclude that from the protection of your policy the same way not having a certificate of compliance gives them an out in the event of a claim.