Karen says the birds were welcomed at Te Tupoko O Te Whenua Marae at Tarata and released into the bush in the Pouiatoa Conservation Forest, about 40 minutes inland from Inglewood, after a short helicopter flight.
Anaru Marshall from Ngati Maru says reintroducing the species is very exciting for iwi.
"Apart from being a great ecological project, it signals a regeneration of the land. It shows the forests are healthy and pests have been eradicated.
"We see this as part of the big picture of enhancing the land and a predator-free Aotearoa, which will benefit all New Zealanders for the future," says Anaru.
Methanex New Zealand public affairs manager Juliet Larkin says Methanex staff have been part of a force of volunteers helping with access tracks and are proud to be part of the project.
"It's important for us to be supporting this project in the Waitara River catchment area, helping enhance the ecosystem and restore this special area on our back doorstep so that the call of the kōkako can be heard again in the hills."