Great Mercury Island, off the north-east tip of the Coromandel, was home to native geckos, weta, tuatara, kaka, kakariki and other birds which were threatened by rats and feral cat populations.
The 1872ha island is open to the public.
Conservation Minister Nick Smith, who was appearing before a select committee this morning, defended the use of public money on private land.
"I don't think our native species care too much as to whether it is public land or private land.
"If there is an opportunity to make islands like Mercury pest-free and that the landowner is prepared to make the bulk of the contribution, I am quite comfortable about the Government making a contribution too to achieve that conservation outcome." He added: "Whether it be iwi, or whether it be Sir Michael Fay, what we're interested in these partnerships is maximising conservation gain." The minister pointed to other partnerships with wealthy individuals, including Gareth Morgan's pest eradication programme on the Antipodes Islands.
He said DoC's advocacy role was not affected by its partnerships with private companies or individuals.
DoC is about to begin a massive pest-control project known as Battle for the Birds.
A significant increase in 1080 poison drops is planned to cope with the mast year, in which beech trees produce more seeds than usual, leading to larger mice, possum and stoat populations.
The select committee heard the massive pest control programme was being funded by savings made from DoC staff redundancies.
Green Party conservation spokeswoman Eugenie Sage said this was a highly insecure source of funding for protecting New Zealand's biodiversity.
