This story has been updated to reflect the number of orbital launches.
Kaitorete Spit is being considered as a site for multiple launch pads by a joint venture.
The joint venture running the project on 1000ha of the spit beside shallow Lake Ellesmere is gauging demand from international space companies and asking them what they need.
International commercial and military demand has been growing rapidly since 2020 for launches of the small and cheap type of satellite that Kaitorete is well suited for.
The Tāwhaki National Aerospace Centre which was set up four years ago, has recently opened a small runway and hangar on the spit.
It told RNZ it had "the potential to scale up the centre, working with the appropriate partners, to cater for multiple vertical launch sites".
"We've also been talking to international companies to understand sector demand and potential infrastructure requirements for vertical launch," chief executive Linda Falwasser said by email on Tuesday.
The National Space Agency said it had funded Tāwhaki to investigate and "the government ... is expecting a business case to be finalised later in 2024".
The spit could fit up to six launchpads, a report to the government in 2020, released under the OIA, advised.
"The maximum possible number of launch pads is six micro-small pads or three heavy launch pads," it said.
However, it was more likely to get two or three pads for launching small or micro-size rockets under five tonnes each, depending on how much area was needed for emergency debris dispersal (up to 15km, though Elon Musk's SpaceX rockets use much less).
The aim is to get pads that multiple companies can use, whereas the country's only existing launch site, at Māhia, is exclusive to Rocket Lab.
The 2020 Kaitorete report assessed demand worldwide - including of Russian rockets since banned in the US - and said tax breaks would need to be offered.
"Incentives (land lease, facilities, tax incentives etc) are necessary to encourage investment," it said.
However, the space agency on Tuesday dismissed that.
"There are no plans at this point in time to provide financial incentives to any potential launch provider," space agency acting head Robyn Henderson told RNZ in a statement.
The government has put about $30 million into Tāwhaki.
The 2020 market assessment of Kaitorete excluded rockets from China, Iran and North Korea, and rated overall demand as, at best, "low to medium", yet it was upbeat about the spit's attraction to a wide range of aerospace users, for access to the likes of polar orbits, sun-synchronous orbits and high inclination orbits.
Launches to the south are the most attractive, but would have to fly over the spit's western dunes, and full environmental impact and flight safety studies were needed, the report said. It briefly considered the pollution risk from various types of toxic rocket fuel, and said launches to the east should be looked into.
It suggested future uses could include as a "hypersonic testbed" (hypersonic development is becoming a feature of the "great power" space race in which the US has pitted itself against China and Russia).
Henderson said the 2020 Bryce and earlier so-called 'Lighthouse' reports on Kaitorete remained relevant. These focus on commercial space flight, to expand the country's $1.8 billion aerospace industry.
There was "clear and immediate" domestic interest for launchpad and runway launches. Internationally, vertical launch is the largest market, and most launches are of medium-lift rockets, in a global launch market worth anywhere between $7 billion and $25 billion last year.
The reports outlined several possible models for the spit, such as a launch-pad developer building the pads, with surrounding infrastructure put in place by Tāwhaki, better roads from Christchurch, and then rocket companies paying for individual launches.
Questions over security
Questions remain about Kaitorete's place in the country's national security framework.
The national space policy has little to say about the military but a lot to say about security, yet the Bryce report on the spit does not go into it.
New Zealand is increasingly active in initiatives led by the Pentagon's US Space Force, which is ramping up launches to try to cement in "space superiority" by 2027.
Its new space strategy is to use allies and commercial space companies much more, and switch from relying on large, hugely expensive satellites to hundreds, if not thousands, of smaller, cheaper satellites.
That will require a lot more launches.
"We need launch capabilities in the Southern Hemisphere," a top director said, at a US-Australia meeting last October.
"We've got to get through the hurdles that we have, the regulatory problems, to enable our closest and best friends and partners - who are very capable with very awesome geography - to be able to do this, and then we spread that out," Deanna Ryals was quoted saying.
The 2020 Kaitorete report said regulations should allow "flights to take place without major burdens".
The US and New Zealand have a Technology Safeguards Agreement to safeguard technology used in US launches in this country, while stopping launches here by any country under UN sanctions or determined by the US "to be contrary to its laws, regulations or policies".
The country has done 40 orbital launches involving 110 payload permits applying to more than 170 satellites.
The 2020 report included among potential customers Russian Angara, Proton and Soyuz 2.1 rockets - a Soyuz launched what the Pentagon called a "counterspace weapon" in May, which Russia denied, according to the Washington Post.