Fresh off the Central Interceptor, tunnelling expertise and capability are now rolling straight into the next phase of work - a new wastewater pipeline in Herne Bay that will help unlock the full environmental benefits of the landmark project.

Watercare has signed a contract with Italian tunnelling specialists Ghella to deliver the Herne Bay Collector - a 1.7-kilometre-long, 2.1-metre-diameter wastewater tunnel in Auckland’s Herne Bay that will connect into the Central Interceptor and significantly reduce wet weather overflows into the Waitematā Harbour.

The move signals more than just the start of a new project. It reflects the scale of investment underway in Auckland’s water infrastructure, and New Zealand’s growing ability to attract and retain world-class delivery partners.

“We’re investing at record levels to maintain safe, reliable and resilient wastewater and water services for a growing Auckland region now and in the future,” says chief programme delivery officer Mark Crowle.

“The project is part of one of the most significant upgrades to wastewater infrastructure in Auckland’s history. Over the next 10 years, Watercare will invest approximately $13.8 billion to improve the region’s drinking water and wastewater infrastructure.”

Rather than leaving at the end of the country’s largest ever wastewater project, Ghella will transition directly onto the next phase of work, keeping people, expertise and equipment on the ground in New Zealand.

“For us, this continuity matters. We’re very pleased to have Ghella on board for this project, following their excellent work on the Central Interceptor. We can keep this capability here and maintain momentum. We’re proud to work together to deliver this essential infrastructure for Auckland,” says Crowle.

The Herne Bay Collector is part of a wider programme of work building on the Central Interceptor, a 16.2-kilometre wastewater tunnel running from Herne Bay to Māngere.

The southern half of the tunnel has been live since early 2025 and the northern half is due to go live in mid-2026, making the tunnel fully operational and enabling the next phase of environmental benefits.

The $260 million Herne Bay Collector will extend those benefits, capturing wet weather overflows from some of Auckland’s oldest combined wastewater and stormwater networks and directing them into the Central Interceptor for treatment at the Māngere Wastewater Treatment Plant.

Once complete, the project will include a 2.1-metre-diameter tunnel, seven main shafts and three intermediate shafts connecting into the network infrastructure that will improve water quality in the Waitematā Harbour and surrounding coastal areas.

“Ghella is proud to continue our journey with Watercare through the Herne Bay project, building on the strong relationship established during the Central Interceptor. This contract reflects the trust built over time and a shared ambition to deliver meaningful outcomes for Auckland,” says Ghella country director for New Zealand Rosario Barresi.

“Together, we are contributing to the protection of Auckland’s coastal waters and helping to improve its beaches and surrounding areas for future generations.

“Working with Watercare has been, and will continue to be, a cornerstone of our long-term commitment in New Zealand, a country where Ghella feels at home.

“Guided by our vision to ‘leave a better world for future generations’, we remain focused on building excellence in a sustainable and innovative way, delivering lasting value to the communities we serve.”

A karakia and cultural induction led by Ngāti Whātua Ōrākei was held on 8 May to acknowledge the contract signing and help ensure a strong official start to the project.

Waitematā Local Board chair Alexandra Bonham attended the event and says the Herne Bay Collector and Central Interceptor have long been advocated for by the community and are much welcomed.

“These combined projects will enable significant environmental gains – they will directly improve wastewater overflows and have a positive impact on the health of the Waitematā Harbour.

“The work in Herne Bay will cause some disruption and we are grateful for the community’s patience, but we are all looking forward to the long-term benefits of this infrastructure - improved water quality and swimmable beaches.”

Construction is under way, with the project is expected to be finished in late 2028.

About Watercare

Every day, we supply about 440 million litres of safe drinking water to 1.7 million people in Auckland. We also collect and treat their wastewater.

Over the next 10 years, we will carry out more than 1000 projects to improve and expand our water and wastewater infrastructure – investing an average of $3.8 million every day ($13.8 billion in total).

Our infrastructure investment programme will help to keep our precious environment healthy by reducing the frequency of wastewater overflows onto land and into waterways.

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