The Auckland-Puhoi motorway will be extended as far as Te Hana on Northland's southern boundary - but work on the $1.3 billion project won't start until 2014.
The new State Highway One won't be an upgrade of the current highway, but will follow a new route west of Warkworth and around
the east of Wellsford before rejoining the existing road just south of Te Hana.
Puhoi-Wellsford project manager Brett Gliddon told this week's Northland Regional Council meeting in Kaikohe that the New Zealand Transport Agency had opted for a new highway because the existing 38km of road was "in a terrible state", and it would allow a more efficient route. Keeping traffic flowing during an upgrade would be difficult, he said.
The new motorway would have interchanges linking it to central or northern Warkworth and central Wellsford.
Unlike earlier proposals, it would pass around the east of Wellsford, making a better link to Mangawhai.
The biggest geotechnical problems were around Wellsford where a 15m layer of loose material was "slipping and sliding around".
It could be built in stages, with the most beneficial sections built first. No decision had been made yet on whether the new highway would be tolled.
The new Orewa-Puhoi motorway charges a $2 electronic toll for cars and motorbikes.
As a state highway, construction would be entirely funded by Central Government.
The plans would go out for a second round of consultation later this year, with consents and designation next year and construction planned to start in 2014.
Regional council chairman Mark Farnsworth queried Mr Gliddon about the "disturbing comments" coming out of the Auckland Regional Council about the Puhoi-Wellsford project.
Mr Gliddon said it was true that the Auckland body had questioned the need for the new highway, and wanted the money spent in Auckland instead.
But the Auckland Regional Council would be dissolved in a few months' time as part of the Super City reforms, he said.
Cr Joe Carr wanted to know if the same amount of money could see State Highway One three-laned all the way from Warkworth to Whangarei, sparing Northlanders from bad roading.
