I had a read and it seems like their decision was reasonable.
To summarise:
They concluded it would be a big plus on strategic/foreign policy grounds, and would have limited economic and tactical benefits (more opportunities for the army/navy to train with fast jets).
If you don’t mind, let me share a frank perspective.
There are tactical benefits for the navy, as F-15SG is configured for maritime strike to compliment the search area of a MPA. To fly low level and to pop-up for strike (which will compliment NZDF’s P-8s). This is deliberately omitted in the papers. When they talk about foreign certification, it’s for SAS certification but they omit the benefit of training for joint fires by normal FOs, which is being done for our army. It’s what is omitted that we can spot easily.
It’s written to sell a point of view.
It would have required a runway extension, the purchase of several properties due to unreasonable noise levels, significant investment in noise insulation on base and in the surrounding town, and increased pollution from noise, fuel burn, munitions and countermeasures. There were also reservations in the NZDF regarding the challenges of operating fast jets and slower training/rotary wing aircraft from the same base, and concerns that the limited development real estate at NZ's major airbase would be taken up.
It’s an airport - more flights means more CO2 (the foot print of Changi and our skies are more crowded), which can be mitigated by purchase of local green credits. We can restrict use of flares if that is a concern (it’s just a little less realism in training). Do you drive? If you do, you have a carbon foot print.
But I recognise that there will be INCREASED costs for NZDF but the people in these forces will be closer. And if shooting starts in a mission, these peace time training relationships will be tested - we currently train in NZ with your guys before we deploy to Iraq and in the papers (just well hidden in a one liner, to ensure it’s not easily spotted by a layperson like me). Likewise for 6 years in Afghanistan and millions SAF spent supporting projects and missions there, along side NZDF.
It sounds like short terms visits from Singaporean F-16's at least will continue, and options for development of a more permanent base for them elsewhere (i.e. Waiouru) considered. I wouldn't hold my breath on that front though.
Why? We want to train with NZDF and increased realism via close air support is good training value. NZDF defended us, when we as a country was much less capable of defending ourselves. We just want to give back and the local Mayors want this.