Plans to completely eradicate Stewart Island of pests have been unveiled by anti-cat crusader Gareth Morgan.
The project would see the island become the first predator free island with a human population in the world.
Dr Morgan said the project could cost around $40 million to carry out.
"We don't really have the techniques yet to do such a large area. Current techniques you'd do an island pretty quickly but you can't do this island quickly it's just far too big for that."
Dr Morgan said he will work with the Department of Conservation and local community groups to see how the project could be run.
"The biggest island DOC have done so far is 11,000 hectares. This island's 170,000 hectares so the magnitude of the job is enormous compared to anything attempted before."
While it could take some time to complete, he said the project would have major economic and environmental benefits.