The plan hinged on getting approval from the Overseas Investment Office (OIO), the government agency which decides whether 'sensitive' land such as farms or coastal land can be sold to foreigners.
Approval was granted in a decision released earlier this week.
The OIO report stated Kayne had applied to lease 144ha of land and buy 25ha at Te Arai South for two links-style championship-level golf courses, along with a clubhouse, visitor accommodation, maintenance facilities and water storage.
The total cost of the lease and purchase is $3.49 million.The report also said the development would lead to 40 jobs, $6m in export earnings by the end of 2022, and at least $25m in investment. Kayne would also carry out planting and weed and pest control.
In an interview with the Herald last year Kayne said he had spent $100m developing Tara Iti and planned to spend another $50m-plus developing the two new courses.
The leasehold land formed part of Ngāti Manuhiri's Treaty settlement. Ngāti Manuhiri has been contacted for comment.
The existing golf course is next to Mangawhai Wildlife Reserve, a key breeding area for the fairy tern or tara-iti. Fewer than 40 terns survive, making it New Zealand's rarest bird.
The new golf courses will be further south but Heather Rogan, convener of the Fairy Tern Charitable Trust, still had concerns about the development.
If the birds' population was to increase they needed more places where they could breed.
Next to Poutawa Stream, at Te Arai South, was one such place, Rogan said.
Two new golf courses on sandy soil would require ''vast quantities of water'', which could affect the stream level, fish numbers, and fairy terns which ate fish from coastal streams.
The trust was already involved in legal action around a dam on Te Arai Stream which supplied water to Tara Iti Golf Club, she said.
Kayne and his wife Suzanne normally live in Los Angeles. Forbes puts his net worth at US$1.1 billion ($1.8b). They are understood to be building a home next to Te Arai Beach.
The members-only Tara Iti Golf Club hosted former US president Barrack Obama when he visited Northland in 2018.