About 230,000 hectares of the region will be targeted in this year's Battle for our Birds programme, which focuses on western and southern parts of the South Island.
The region is home to numerous anti-1080 activists, who oppose continued use of the poison.
The Department of Conservation (DOC) led project will be the largest pest control operation in New Zealand history, surpassing 2014's programme in both cost and scope.
Work began last week, with drops of non-toxic bait in Fiordland and South Westland.
The timing of individual 1080 drops would depend on factors including weather, bait supply, and rat tracking levels, a DOC spokeswoman said.
The drops would continue into spring.
DOC received $20.7 million from this year's Budget for the programme, to combat what conservation minister Maggie Barry described as a "biblical" plague of rats, caused by beech masts.
The list of confirmed drop sites nationwide covers 720,000 hectares of land, and includes places that weren't subject to drops in 2014.
The largest drop is planned for Kahurangi in the northern South Island – poison will be dropped across more than 300,000 hectares of land, an increase from 270,000 hectares in 2014.
A new area targeted are the Murchison Mountains, in Fiordland National Park.
1080 will not be dropped in the area — funding will go towards enhancing the existing trapping network, which protects the local Takahe population.
Other new areas targeted this year include Okarito near Harihari and Mokihinui near Westport.
Some areas will be targeted again, with greater coverage than in 2014.
They include Makarora near Wanaka, and the Haast range and Landsborough in South Westland.
Drops may also occur in parts of North Canterbury and Maruia near Lewis Pass, but had not yet been confirmed.
Use of the poison is supported by most conservationists, including DOC, Forest & Bird, and Parliamentary commissioner for the environment Dr Jan Wright.
It remains contentious in some areas, due to the harm it can cause native birds and non-targeted mammals that consume 1080.
Protesters have threatened action against a planned 1080 drop in Taranaki, and protests are likely in the South Island, where 1080 opposition is most concentrated.
Bill Wallace, founder of the Ban 1080 political party, said he continued to oppose DOC's use of 1080 and believed it did more harm to native birds than good.
There were no formal protests planned from his group, he said, but it would continue to voice opposition.
"They're [DOC] going to do more harm to native birds in the upcoming drop," he said.
"The rats... will be back up to equal or higher numbers next year and the birds will just be one step closer to extinction."
Main drop sites:
Kahurangi, north-west South Island (around 300,000 hectares)
Makarora, Otago (38,942 hectares)
Mokihinui, West Coast (35,584 hectares)
Taranaki, North Island (34,000 hectares)
Haast Range, West Coast (31,516 hectares)
Sourced from: http://www.stuff.co.nz/environment/83210402/massive-1080-pest-control-operation-to-begin-on-west-coast