Auckland's water company has struck a deal which it hopes will allow it to dump solid waste on an island in Manukau Harbour.
The treated bio-waste from the Mangere wastewater treatment plant would help to fill in a quarry to create a regional park on nearby Puketutu island.
The agreement between Watercare, iwi and the island's owners, the Kelliher Charitable Trust, would also create a marae and cultural centre.
It still needs the approval of the Environment Court.
A 55-year lease for the island will cost Watercare $27 million and it will pay a $2 a tonne levy for waste.
The company says not having to transport the waste further away will save it $22 million over the life of the project.