Skip to: Navigation | Content | Footer

About this project

Updated: 21 November 2012

The 27-km Transmission Gully route forms the MacKays to Linden segment of the Wellington Northern Corridor which runs from Levin to Wellington Airport.

There will be an interchange connecting the route to State Highway 58, and another to the Porirua City Centre and Linden through Kenepuru. In addition, there will be two link roads connecting the eastern Porirua suburbs of Whitby and Waitangirua to the route. The Porirua City Council will be the authority responsible for the Whitby and Waitangirua link roads.

Water quality test.

In 2008, during Phase 1 of the Transmission Gully project, the NZTA undertook public consultation on the preferred route through Transmission Gully. The consultation resulted in 88.6% of respondents supporting the preferred route.

In 2010, during Phase 2 of the project, engagement on design and environmental matters was undertaken with iwi, community groups, statutory agencies and territorial/local authority stakeholders in preparation for the lodgement of Notice of Requirement (NoR) and resource consent applications with the Environmental Protection Authority (EPA).

In September 2010, the NZTA lodged a request with the Environmental Protection Authority (EPA) seeking changes to the Wellington Regional Freshwater Plan to provide a clearer policy framework within which resource consent applications for activities in and on water bodies can be considered.

A Board of Inquiry hearing was held on the request in July 2011 and the Board announced its final decision on 10 October 2011. Details of the final decision can be accessed on 

On 15 August 2011, the NZTA lodged the applications with the EPA and detailed information on the applications, process and timeframes can be obtained on

On 24 August 2011, the Environmental Protection Authority (EPA) recommended to the Minister for the Environment that the regulatory consent applications lodged for the Transmission Gully project be directed to a Board of Inquiry as a proposal of national significance. Information on this can be accessed on the EPA website.

On 16 September 2011, the Minister for the Environment directed that the applications be referred to a Board of Inquiry. The Ministerial direction can be accessed on

The Minister for the Environment's media statement on the applications referral can be accessed on

The EPA's public notification of the applications can be accessed on

The NZTA's media statement on the applications referral can be accessed on

The Minister of Transport's media statement on the applications referral can be accessed on

The Board of Inquiry’s hearing on the Transmission Gully applications was conducted from 13 February 2012 to 15 March 2012.

The Board of Inquiry’s draft decision was released on 4 May 2012 and can be accessed on the EPA website.

On 22 June 2012, the Board of Inquiry released its final decision on the Transmission Gully applications. The Board’s decision can be accessed on

In August 2012, the Minister of Transport directed the NZ Transport Agency (NZTA) to assess the suitability of using a Public-Private Partnership (PPP) procurement model to design and build the highway.

Following an extensive business case analysis (using the Treasury’s better business case framework), the NZTA determined that the project meets the Treasury’s criteria for a PPP procurement model.

On 21 November 2012, the Cabinet gave the NZTA approval to finance and build the Transmission Gully highway using a PPP. The NZTA was also given approval to borrow up to the estimated costs of traditional procurement as part of the PPP. Final approval of the borrowing limit will be confirmed by the Cabinet before the NZTA awards the PPP contract.

Expected PPP timelines

The following are the expected key stages and timelines for establishing a PPP for the Transmission Gully project:

  • November 2012 (Announce Registration of Interest: To identify consortia interested in and capable of delivering the required services)
  • January 2013 (Announce Expression of Interest: Potential consortia are asked to provide information on their capability to do the work)
  • April 2013 (Identify shortlist of PPP consortia)
  • Mid-2013 (Issue Request for Proposal: Formal bids on the project requested from the shortlisted consortia)
  • End-2013 (Request for Proposal closes)
  • Mid-2014 (PPP contract awarded)

Construction would begin by late 2014 and the highway would open for traffic by 2020.