Poor weather prevented the possum control operation over 10,900 hectares of bush and forest between Akatarawa Road in Reikorangi and the Ōtaki River prior to the Christmas-New Year period, when the area is popular with recreational users.
Its North Island programme manager Alan Innes said the the operation was designed to prevent the spread of bovine tuberculosis (TB) infection from wildlife into neighbouring farms and lifestyle blocks.
"Removing possums and also rats brings biodiversity benefits for the native plants and birds," he said.
He said the rugged nature of the terrain and the inaccessibility of the targeted block made aerial control the preferred method.
Ground-based possum control methods such as traps and poisons would be used on flatter land nearer areas of population and recreational parks.
However, some residents who lived near the operation area were not convinced the use of 1080 was the answer.
Wilf and Janet Wright, of Reikorangi, said they knew many people who were also opposed to the aerial operation.
"As far as I'm aware New Zealand is one of, if not the only countries using it. Why do we need to take such extreme action? I don't think the end result justifies the means to achieve it," Wilf said.
"The bigger problem for native and endangered birds is the destruction of their natural habitat by development."
Fellow Reikorangi resident Rick Swan said although he was comforted by improvements in the way possum control operations were managed, he felt there must be better methods than aerial 1080 drops.
"I've lived here for 21 years and this is the driest it's ever been. The possums and other animals will have headed towards the rivers, so my concern is them dying and decomposing in the water.
"Also, I'm worried about other effects, such as predators such as the New Zealand falcon and harrier hawk eating contaminated possum carcasses."
Swan said the possum fur trade could be focused on.
"One year I let a guy go possum trapping in my forestry block and he made just over $3000 from possum fur in three days."
Ospri's possum control operation was planned for February with the exact date yet to be announced.
The area included walking tracks of the Mangaone Walkway, Kapakapanui Track and Hut, Waiotauru and Parata tracks.
Signage at all public access points to tracks and huts would be installed to alert hunters, hikers, mountain bikers and people with dogs. Free dog muzzles would be available.
Ospri chief executive Michelle Edge said in addition to eradicating pests and TB, another goal was to enhance an important air corridor for birds travelling between Kāpiti Island and the mainland forests above Waikanae.
"Kāpiti [Island] is a predator-free sanctuary where birds can survive and breed untroubled by introduced possums, rats and stoats.
"Their sustaining habitat of native bush offers food, safe nesting and shelter, undamaged by pests.
"That balanced biodiversity is still a dream on the mainland, but in the first months of 2018, it will come significantly closer."