On the assumption the NZ AIP is correct in implying that FIS delivery responsibility still lies with Australia
Is this the section that the NZ are relying on?
2 AREA OF RESPONSIBILITY
The AIP service provider and the NOTAM service provider are responsible for the collection and dissemination of information necessary for the safety and efficiency of air navigation throughout New Zealand’s area of Norfolk Island
2.2.13 Norfolk Island is located within the Auckland Oceanic FIR and is administered by Australia.
2.2.14 Information regarding services and operations at Norfolk Island is contained in the AIP Australia.