ACCIONA's first project in New Zealand

Construction of 18.5 kilometres of highway with four lanes between Puhoi and Warkworth with 110 km design speed.

The project includes the design, construction, financing, operation and maintenance of the SH1 Highway Expansion in northern Auckland.


The public-private partnership (PPP) contract award to build the stretch of the Puhoi-Warkworth highway is ACCIONA's first project in New Zealand, which consists of the 18.5-kilometre four-lane North Highway extension from Johnstone Hills tunnels to North Warkworth.


This is the first stretch within the Ara Tūhono - Puhoi to Wellsford passage, which will contribute to the economic growth of the Northland region and provide a more reliable and secure transportation link with the triangle formed by the cities of Auckland, Waikato and Tauranga. Traffic from the Puhoi to Warkworth highway is scheduled to open in 2022.

General Information

  • Location: Auckland, New Zealand
  • Type of contract: PPP (30 years)
  • Infrastructure: Highway extension
  • Construction end year: 2022

Key figures


km of two-lane highway


km/h design speed


long viaducts




drainage collectors in two basins: Pūhoi and Mahurangi River.


cubic metres of earthmoving for clearing


cubic metres of earthmoving of embankments.

Technology and innovation

Geometric optimisation

Acciona was awarded the project in 2016 by the New Zealand Transport Agency after an 8-month competitive dialogue process where engineering value was considered one of the Client's main criteria. 

Geometric optimisation guided the design throughout the process based on a cost-effective solution using a field-adjusted curvilinear alignment where the operating speed criteria allowed for the best design. A consequence of the terrain-adapted geometry is that the new alignment offered fewer structures and shorter viaducts. The final result was a reduced total length of structures from 2,350 m in the Conceptual Design to approx. 800 m long in the final design.

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