The route chosen for the Mt Messenger bypass on State Highway 3 is the most resilient option on the table, the Transport Minister says.
Simon Bridges announced the choice at the northern Taranaki settlement of Mimi today.
The new route, which will be east of the existing road, was the least favoured by the transport lobby, but the one championed by iwi and conservationists.
Known as Option C, the route was considered the least ecologically damaging of the five proposed and was only added into the mix in June after consultation with iwi and the public.
The transport sector and many motorists favoured a more direct route, Option A, but that would have crossed Ngāti Tama land, where endangered kōkako have recently been reintroduced.
Mr Bridges said there were also major geotechnical issues with options west of the existing road.
"Effectively active landslides that meant to build on that side would have either been a very expensive technical challenge, possible insurmountable."
Mr Bridges said the eastern route would be shorter and straighter than the present road, and not as steep as western options.
He said State Highway 3 was the key link between Taranaki and the Waikato, and the new bypass would help improve safety and contribute to the region's economic growth.
The NZ Road Transport Association said it was happy the right choice had been made.
A Ngāti Tama iwi member said she was overjoyed that the bypass would veer away from the bush where kōkako had recently been reintroduced.
Officially Ngāti Tama said it was still considering the decision, but iwi member Susan White, who was at the announcement, said they will be happy with the move.
"Everyone is going to be so pleased that the forest isn't going to get cut in two. That's a big thing. I just can't wait to get home and ring up and tell people.
Ms White said the iwi and conservationists had spent decades trapping to make the forest safe for kōkako, and if the western bypass option had been chosen that work would have been put at risk.
But a local farmer whose property lies in the way of a proposed bypass fears he will be forced out of his home.
The highway's path east from the existing road would see it veer towards Happy Valley, where Tony Pascoe farms beef cattle on 115 hectares.
Mr Pascoe said the project would dissect his property and, at its peak, force him out of his home.
"I held myself together pretty well yesterday, but when they left the reality starts to hit, and you start to think, 'Well, you're not going to have a home'."
The route of the new highway was notorious for fog and black ice, and could end up becoming a death trap, Mr Pascoe said.
Mr Bridges said he felt for those in the path of the new road, but he was confident the Transport Agency would deal with them fairly.
Construction of the bypass is due to begin next year and be completed in 2021.