Some ecologists are warning the push for New Zealand to become predator-free could do more harm than good to native wildlife.
They fear ramping up efforts to eradicate introduced predators, such as cats, rats, stoats and possums could come at the expense of species already on the brink of extinction.
Predator Free New Zealand wants to rid the country of pests, to help native species thrive.
But others point to a risk that wiping out some predators at the top of the food chain, such as stoats, might inadvertently put native species in even greater peril by boosting the numbers of predators further down the chain.
Ecologist John Innes, from Landcare Research, told Nine to Noon that focussing on certain predators could allow others to flourish.
"If you control everything, then you get more mice. Mice are actually rare because they're eaten by everything, but if you take everything away, as you do in most sanctuaries, you can end up with just mice and they end up more abundant then they were before," he said.
Graeme Elliott from the Department of Conservation (DoC) said getting rid of predators in the long term was a good thing, but it needed to be done carefully.
"There could be all sorts of extinctions on the mainland happen over the 10 or next 20 years that would be very hard to recover, even if we did [become pest-free] way down the track.
"I don't want to rubbish the vision, because I think it's great, it's what we all dream of, but we've just got to be cautious to balance where we spend our efforts."
Dr Elliott said becoming pest-free should not come at the expense of existing conservation efforts.
"If you redeployed resources towards Predator Dree New Zealand from existing conservation efforts you could lose some species which are already on the brink."
Predator Free rejects criticism
Predator Free New Zealand rejected the criticism that its plan to eradicate introduced pests could harm native wildlife.
Its chairman Devon McClean said the benefits of becoming predator-free would outweigh the possible consequences.
He said the impact predators had on wildlife was devastating and the time to act was now.