The Department of Conservation will review its poisoning procedures after 700kg of rat bait fell from a helicopter into a Fiordland lake last month.
An investigation into the incident found it was caused by strops being incorrectly located on a pod carrying the rat bait.
Doc has subsequently agreed to adopt a recommendation from the investigation that bait pods are standardised and secure when used for animal pest operations.
"The findings from this incident will help us improve how we undertake island pest eradications," Doc Southland Conservancy conservator Barry Hanson said yesterday.
"New Zealand is a world leader in this type of work and a large part of our success has been from us not just maximising those aspects that have been really successful, but also from learning from when things go wrong."
The investigation was launched after 700kg of brodifacoum cereal bait pellets in plywood boxes on a pallet suspended under a helicopter detached in flight and fell into a lake between Anchor Island and Indian Island during the Doc poisoning operation in June.
Ongoing monitoring of water samples in the area by Landcare Research had found no trace of toxin, Mr Hanson said.
Anchor Island is pest-free and home to the endangered kakapo, saddleback and mohua.
