The 1080 debate has hit the courts - and the lawyer in charge is arguing that for the first time, this is a debate about human health, not just bird health.
A conservation group has won a temporary injunction in the Environment Court to stop a 1080 drop on south Auckland's Hunua Ranges, but a conservation biologist say the science cannot be argued with.
Scientists say that without 1080, our forests will turn silent.
"If there's no 1080, it becomes this almost poetically silent forest - as you walk through it you don't hear anything," Associate Professor James Russell says.
A non-toxic pellet drop happened in the Hunua Ranges earlier this month, marking the last step before 1080 is used. Almost simultaneously, court action was filed to stop that happening later this week.
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The Auckland Council is confident there are no grounds to halt the dump. It says similar arguments have been refused by the High Court previously.
"We believe these proceedings provide no grounds to halt the council's pest management programme," it says.
"The arguments raised in the application have been refused by the High Court in previous proceedings brought by the same applicant."
But the lawyer in charge says this case is different - it's about human health.
"We are playing an experiment on the people of New Zealand while we are putting this poison that's known to have possible fertility and cumulative effects into New Zealand water supplies," Sue Grey says.
The Hunua Ranges supply around 65 percent of Auckland's drinking water, so during the 1080 dump, the four large water reservoirs will be protected by buffers of 20 to 50 metres, and there will be extensive water monitoring during and afterwards.
But Ms Grey says it's "far from fool-proof".
"The whole catchment where the rain lands on the ground and runs down into streams and into the reservoir is going to be covered by 45 tonnes of 1080 poison, which is a deadly poison."
Mr Russell says people will always manipulate the facts to suit their argument.
"That's why we want to achieve a predator-free New Zealand - if we can stop having to be locked into this debate of perpetual control and how to do it."
The court's decision is due on Thursday.
Newshub understands plans are still in place to drop 1080 on Friday morning.