New high voltage line to Mangawhai
Location: Maungaturoto to Mangawhai
Start date: February 2026
Completion date: July 2027
Investment: $20 million
Supporting growth and resilience
Mangawhai is transforming. What was once a small holiday destination is rapidly becoming one of Northland’s fastest growing communities, with the population expected to double over the next 30 years. As more people choose to live, work and build businesses in the area, Northpower is investing to make sure the electricity network can support this growth safely and reliably.
To meet increasing demand, we’re constructing a new 34km, 33kV sub transmission line from Maungaturoto to Mangawhai. This second line will strengthen the backbone of the network, improve security of supply for more than 6,400 customers, and support the long-term development of the wider Mangawhai and Kaiwaka region.
Why is this upgrade needed?
Electricity to Mangawhai and Kaiwaka is currently supplied by a single 33kV line, with limited backup supply options.
Peak demand in Mangawhai is increasing, driven by new subdivisions and a growing commercial centre. The Kaipara District Council forecasts the local population to grow from 7,700 to around 15,500 over the next three decades, and at current growth rates, the existing sub-transmission line will reach capacity by 2030.
A second supply line is essential to ensure the area has the capacity, resilience, and reliability expected of a modern urban community.
What we are building
The project includes:
- A new 33kV sub transmission line linking the Maungaturoto substation and the Mangawhai Central substation
- A mix of overhead and underground construction
- The installation of a parallel UltraFast Broadband (UFB) route delivered by Northpower Fibre
This investment follows earlier upgrades, including the new Mangawhai zone substation commissioned in 2021 to support the Mangawhai Central development.
This upgrade will reduce the risk of widespread outages and improve resilience for both Mangawhai and Kaiwaka. It will support new homes, businesses, and infrastructure and provide capacity for Mangawhai’s future growth. It will also deliver digital benefits through the new Fibre infrastructure.
Northpower is committed to building an electricity and fibre network that supports the region’s wellbeing and long-term development. The new Mangawhai 33kV line is a key part of enabling that future.
With and for our community
In February, a blessing was held with Te Uri o Hau of Ngāti Whatua Kaipara to prepare for the commencement of work on the 34km line. We have been working with locals through the design stages and would like to thank all landowners and stakeholders who have supported the project to date. We appreciate your ongoing support while work continues.
There will be traffic management with stop/go controls in place along Baldrock Road and Cove Road from March through June while the work to build the first section is completed. We apologise for the inconvenience this may cause and thank you for your patience during this time.
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New high voltage line to Mangawhai
