Central Interceptor


Prospective pipeline

Credibly proposed


Under procurement

Preferred bidder announced

Recently closed
Central Interceptor

Prospective pipeline

Greenfield (construction) or brownfield (government asset divestment) projects needed or likely to occur within the next five years, but is not formally proposed by a state, territory or major local government.

Credibly proposed

The project or divestment is supported by a state, territory or major local government, is subject to studies or other processes (such as pre-feasibility or scoping studies or business case development), and is likely to proceed to formal announcement.   


The project has a firm commitment and timeline from a state, territory or major local government, but has not yet entered the market.

Under procurement

The project or transaction is under procurement (such as a call for Expressions of Interest, requests for tender, or another offer to the market).

Preferred bidder announced

A preferred bidder has been selected and is in exclusive negotiations.

Recently closed

Projects that have progressed to contractual close remain on ANZIP for 12 months.

ANZIP is focused only on major infrastructure activity, above the following thresholds:


Construction projects: > AUD$300m

Investable greenfield & brownfield: > AUD$100m

New Zealand

All greenfield and brownfield projects and divestments: > NZD $100 million

STATUS: Recently closed
VALUE: $1.12bn AUD | $1.2bn NZD
SECTOR: Water & sewerage
PROCUREMENT APPROACH: Traditional procurement
TYPE: Greenfield

The Central Interceptor project involves construction of a new wastewater tunnel proposed to run between Western Springs and the Mangere wastewater treatment plant in Auckland and link sewers conveying wastewater to the tunnel. 

The Central Interceptor provides additional capacity to the network to accommodate population growth in Auckland and to reduce overflows to the Waitemata and Manukau Harbours during wet weather. It will also duplicate the lower sections of the Western Interceptor, including the Hillsborough Tunnel and Manukau Siphon which are ageing and could lead to continuous discharge of untreated wastewater into Manukau Harbour if it fails.

The main tunnel will be approximately 13 kilometres long and will lie between 15 and 110 metres below the surface. It will cross the Manukau Harbour at a depth of approximately 15 metres below the seabed. Along the proposed route, it will connect to the existing trunk sewer network to divert flows and overflows into the tunnel.

Auckland Council-owned utility Watercare is overseeing construction of the project. An Auckland Council-appointed hearing panel granted Watercare's application for resource consents for the Central Interceptor in November 2013, with the Central Interceptor estimated to increase annual volume of treated effluent entering the Manukau Harbour by two per cent and have no measurable impact on water quality.

Watercare began a competitive tender process in 2017 with Expressions of Interest closing on 29 November 2017. In March 2018, Watercare announced the contractors who had been shortlisted in the selection process, which were:

- CPB Contractors;
- Ghella-Abergeldie Harker Joint Venture;
- Pacific Networks, comprising McConnell Dowell, Fletcher Construction and Obayashi; and
- VINCI Joint Venture, comprising VINCI Construction Grands Projects, HEB Construction and Solentache Bachy.

Watercare released design and technical documentation in March 2018 and a Request for Proposals was issued to shortlisted contractors in May 2018. Tenders from the shortlisted contractors were received in September 2018.

In November 2018, the Ghella-Abergeldie Harker Joint Venture was selected as the preferred bidder and in March 2019 a construction contract was signed.

Included in the construction contract are additional projects to be delivered, such as separating stormwater and wastewater pipes. The largest of these projects is the Grey Lynn wastewater tunnel, which is a two-kilometre extension of the Central Interceptor.

Construction of the wastewater tunnel commenced in August 2019 and is expected to be completed by 2025.

Last reviewed: 05/09/2019

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