Abergeldie, in joint venture with Ghella, is engaged as head contractor for construction of the Central Interceptor, a 14.7km long, 4.5m diameter tunnel from which will run underground from Grey Lynn to Māngere Wastewater Treatment Plant. It will have several link sewers and shafts along the route for collecting and transferring wastewater into the tunnel.

Once completed, the tunnel will be one of the longest in New Zealand.

The Central Interceptor will greatly benefit Auckland by providing additional wastewater capacity to serve city growth, while helping to maintain the cleanliness of beaches, estuaries and waterways by reducing the frequency and volume of wastewater overflows.


The 4.5m diameter interceptor tunnel will run underground for 14.7km between 15 and 110m below ground. It will cross the Manukau Harbour at about 15 metres below the seabed.

Scope includes construction of 18 permanent shafts for operational use and future access. Major elements include structures at the connection points such as access shafts, drop shafts, flow control structures, overflow structures, grit traps, air vents and air treatment facilities.


The Ghella Abergeldie Joint Venture is applying knowledge gained from more than 150 years’ combined experience working on major tunnelling, water and wastewater projects of this scale.

Construction of the Project includes 17 surface work sites two major shaft sites at Watercare’s Māngere Wastewater Treatment Plant and May Road in Mt Roskill.  The below ground works for the main tunnel and two link sewers will be constructed using two tunnel boring machines owned by both Ghella and Abergeldie. 

For more information, visit the Watercare website via this link or watch the video via this link. To keep up to date with the Central Interceptor, make sure to follow us on LinkedIn or check our News and Media section.



Current status:

In Progress