Project update

22 May 2025

The project's 'Zone 5' - including Fill 13 and the southern entrance to the 235m tunnel.

Works underway in the north as progress continues across the project

The second quarter of 2025 has seen great progress at Te Ara o Te Ata – Mt Messenger Bypass project in northern Taranaki.

The team recently established a base compound at the northern end of the project, a job requiring traffic management, and we thank road users for their patience while that took place. In recent weeks we’ve installed a kiwi exclusion fence, and limited vegetation clearance is underway after checks for lizards, bats and other wildlife.

In the centre of the project, on the northern side of Mt Messenger, we’re about halfway through excavation of the 40m-tall Cut 10, which sits above a large sediment retention pond (more details below).

We’re continuing to build up the 660,000m3 Fill 12, which leads to Cut 11, where our tunnellers are expected to break through before Christmas this year.

Approaching from the south, our 110t road header, Hinetūparimaunga, is currently excavating 1.2m cuts, then pulling back so that shotcrete can be sprayed and rock bolts drilled in for stability. More than 45m of excavations have been completed to date.

Heading towards New Plymouth, excavated material from the tunnel is building up Fill 13, which leads to the northern side of the future 125m bridge.

On the southern side, we’re making great progress on temporary bridge staging. With the first section established, our 280t crane has moved onto the deck and is installing 12-tonne piles for a temporary structure that we’ll use to build the permanent bridge, which will feature raked piers – angled legs – to minimise impact on the wetland below.

The bridge approach has been shored up with a mechanically stabilised earth wall – a composite type of reinforced retaining wall. The southernmost part of the new alignment is essentially at road level now where it rejoins the existing SH3.

Bulk earthworks are largely complete for this construction season, but our tunnel and bridge teams will continue working at full capacity over winter as we move forward with this much-needed improvement to the state highway network.

Shot by drone, the flyover video gives a birds-eye view of progress.

Watch our latest flyover video

Our latest flyover video is available for viewing on our project website and social media. The video includes a voiceover from project manager Caleb Perry, discussing the great construction progress being made along with our commitment to treading lightly on the land. 

The project's new sediment retention pond treats water from a 5ha catchment area.

New pond furthers environmental protection

Protecting the unique northern Taranaki ecology is a vital part of the project as we tread as lightly as possible on the whenua.

At the forefront of this commitment is our award-winning erosion and sediment control (ESC) programme – and a recent addition is testament to both innovation and care for the environment.

A few weeks ago, our team successfully commissioned a new sediment retention pond (SRP) in the Fill 12 area. An SRP is a temporary pond for rainwater runoff where sediment can sink to the bottom, while clean water is discharged to the environment.

Designed to manage runoff from a 5-hectare catchment, the Fill 12 SRP is two-thirds the size of an Olympic swimming pool by volume and is a key part of our strategy to protect nearby waterways. Built using 15,000m³ of fill material, the SRP will be in place for more than three years, due to the scale of work in the area, so ensuring its long-term effectiveness is critical.

Although sediment deposition within the pond is monitored after every rain event, the structural aspects of the device will also be carefully monitored.  The SRP will be re-surveyed after 12 months to confirm it continues to meet our stringent design specifications. This includes surveying the pond, cleaning the hardware, and sending confirmation to Taranaki Regional Council.

Mt Messenger is a magnet for heavy rain (more than 5 metres has fallen since October 2022) and already the pond has more than proven its effectiveness, coping with a number of rainfall events in a few short weeks.

As with all our ESC measures, this SRP is built to handle a one-in-100-year rainfall event – reinforcing our commitment to building resilience into every aspect of the project.

The Fill 12 SRP is another example of how we are delivering infrastructure while protecting the mauri of the land and waterways at Te Ara o Te Ata.

Ngāti Tama members are deeply involved in the project's day to day mahi.

Guardians of the whenua – the integral role of Ngāti Tama

The full support and partnership of mana whenua, Ngāti Tama enables Te Ara o Te Ata – Mt Messenger Bypass to progress.

Their involvement is both meaningful and essential, with iwi members contributing across all areas of the project – from operating machinery on-site to fulfilling key roles within the project team.

A dedicated group of Tāngata Tiaki (Cultural Monitors) works closely with ecologists to protect native taonga species and waterways. They also play a vital role in documenting the progress of earthworks and construction, ensuring that cultural and environmental values are upheld throughout the project.

Each month, Ngāti Tama whānau involved in the project come together before work begins. These hui provide an opportunity to strengthen relationships, share karakia and waiata, and reflect on how they are embodying the values of Ngāti Tama and the Mt Messenger Alliance along Te Ara o Te Ata.

The Alliance is guided by MANAAKI values of Ngāti Tama —Whakaruruhau (Protection), Tūpato (Caution), Hauora (Wellbeing), Whakamana (Empowerment), Tiaki (Consideration), Aroha (Empathy), Mahi Tahi (Collaboration), and Mana Tangata (Unity).

These principles are deeply embedded in the project’s culture, supporting the health, safety, and wellbeing of all involved.

At its heart, the project is about building a future grounded in mutual respect, cultural integrity, and a shared commitment to the land, the people, and the values that connect them.

More information

For more information on Te Ara o Te Ata: Mt Messenger Bypass, please visit our website, email SH3@nzta.govt.nz or call 0800 BYPASS.