The Transport Agency is a step closer to building Transmission Gully, north of Wellington.
It has announced the two consortiums selected to bid for the contract to build the 27km highway.
They are Wellington Gateway Partnership, led by Leighton Contractors, and Positive Connection, which is led by John Laing Investments.
The successful bidder will fund the road and maintain it over 25 years, and will be repaid by the agency over that time.
NZTA chief executive Geoff Dangerfield said both groups have experience in major infrastructure projects.
The successful bidder will be announced early next year and construction is expected to begin before the end of the year.
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Labour says foreign investors are set to make a profit on Transmission Gully.
Transport spokesperson Iain Lees-Galloway said it's unfair that taxpayers have to pay the increased bill under the public-private partnership.