At present, the islands are part of the public conservation estate. Yesterday, the Department of Conservation could not say how much it spent on programmes such as reintroducing native birds or keeping the islands pest-free.
Co-governance between iwi and the Crown is not on the cards, but the islands will be subject to a new conservation management plan developed with iwi.
Tamaki Collective chairman Paul Majurey said that while there would not be a dedicated co-governance entity, three seats on the Auckland Conservation Board and an equal say for iwi on the new plan could achieve those aims.
The agreement is an important step in settling all historic Treaty grievances in the city - it solves many of the tribes' over-lapping issues, except for their harbour claims, but allows individual iwi to progress their own issues.
This month, Ngati Whatua o Orakei ratified an $18 million settlement and Ngai Tai ki Tamaki signed an agreement in principle for $11.5 million.
The eventual legislation that will deal with the islands updates one signed in February last year which signalled that 11 volcanic cones or maunga in Auckland would be managed under a new co-governance regime between the collective, Auckland Council and a Crown representative.
It is possible that once a bill is ready for Parliament, 15 cones such as Mt Eden, One Tree Hill and Mt Smart - known as Rarotonga to iwi and home of the Vodafone Warriors - will come under the board's jurisdiction.
Mt Smart Stadium is owned by Auckland Council and managed by the Regional Facilities Auckland council-controlled organisation.
Wendy Brandon, Auckland Council's general counsel, said the agreement was clear that there was a process still to be worked through to ensure the protection of existing rights and interests on the maunga including, in particular, Mt Smart.
"The council will be closely involved in this process, and the council has made it clear to the Crown that existing arrangements for Mt Smart must be retained and preserved in all respects," Ms Brandon said.
It costs ratepayers just over $1 million to manage 12 maunga; three others are managed by DOC. What co-governance will cost ratepayers is not known, but a Wellington source said the new regime, barring set-up costs, was not expected to cost substantially more.
Ms Brandon said the Crown had agreed to contribute $400,000 in establishment costs.
IWI COLLECTIVE
* The 12 iwi members of the collective are: Ngai Tai ki Tamaki, Ngati Maru, Ngati Paoa, Ngati Tamaoho, Ngati Tamatera, Ngati Te Ata, Ngati Whanaunga, Ngati Whatua o Kaipara, Ngati Whatua o Orakei, Te Akitai Waiohua, Te Kawerau a Maki, Te Patukirikiri.
* Te Runanga o Ngati Whatua is also a member.
* The four Hauraki Gulf Islands to be vested in iwi before being gifted back to nation are Rangitoto, Motutapu, Motuihe and Tiritiri Matangi