Petone to Grenada

Monthly update

13 February 2026

What’s happening across the project

Updates in this edition:

• The Petone to Grenada investment case has been released.
• Ground and environmental investigations update.
• Upcoming work and how we’re minimising impacts.
• Track closures.
• Common terms explained.

Investment Case released

We’ve proactively released the Petone to Grenada investment case providing valuable insights about the project. You can read it on our website.

Ground and environmental investigations update

We’re currently carrying out ground and environmental investigations in Grenada, Newlands, Woodridge, Horokiwi and Petone. These help us understand soil, land and environmental conditions along the preferred route so we can plan and design the project based on accurate data.

Investigations began in November 2025 and will continue across various sites over the coming weeks. Nearby residents will be notified by letter before work begins.

Image: Ground investigations and drilling equipment on Mark Avenue. 

Upcoming work

Investigations will be happening in Seton Nossitor Park from next week.

In steep or remote areas we’ll use helicopters to help deliver and remove equipment. Before flights, we’ll create landing zones, safe access tracks, and ensure the public has been notified and isn’t nearby. We’ll also take care to avoid homes and people while flying loads.

Over the next 4-6 weeks, helicopter flights will take place from:

• Seton Nossiter Park: the grass area southeast of the carpark.
• Waihinahina Park: the grass area north of the carpark.

Some areas will be cordoned off for about half a day for flights. Some noise is expected during hovering.

Ecology and environmental work

Understanding local ecosystems in Gilberd Bush Reserve and Seton Nossiter Park is a key part of project planning. Our specialists are carrying out:

• Bird counts,
• Invertebrate monitoring,
• Vegetation assessments and habitat mapping,
• Lizard monitoring (ground and tree-dwelling species),
• Wetland and freshwater studies,
• Stream classification,
• Acoustic monitoring for wildlife.

All equipment is temporary, please leave it in place. 

How we’re minimising impacts

We know parks and reserves are important spaces to communities. Where vegetation needs to be trimmed or cleared to complete ground investigations, our teams will leave the roots intact so areas can regenerate naturally. We know this can look concerning, but it will be done carefully. Arborists and Ecologists will supervise, and if vegetation doesn't reestablish naturally, we’ll replant.

We carefully plan all investigation work to minimise disruption, including:

• Borehole locations are chosen to avoid higher quality ecology features.
• Vegetation trimming is carried out carefully, under expert supervision and is approved by Wellington City Council.
• Ecological work is designed to minimise disturbance to native species and their habitats. Habitat checks are performed to avoid wildlife, and adjustments are made on site if needed.
• Arborists climb trees to inspect habitat features in large trees.
• All vegetation is hand moved and stacked around the trimming site.
• Most ground vegetation is left undisturbed to allow for resprouting.
• Equipment will be transported in and out of the bush by helicopter.

How we investigate the ground

• Borehole drilling: we drill narrow holes to learn what’s underground. These can be up to 100 metres deep and drilling usually takes between 1-14 days, depending on the site.
• Window sampling: this is a low-impact way of taking soil samples, using small steel tubes driven up to 10 metres into the ground. Each test usually takes a few hours.

Image: Te Ara Paparārangi Track in Gilberd Bush Reserve is temporarily closed

Track closures

The Te Ara Paparārangi Track in Gilberd Bush Reserve is temporarily closed for two weeks as we have investigation teams working in the area. Clear signage is in place – for your safety, and the safety of others, please do not remove these signs.

A section of Lindsay's Track in Seton Nossitor will be closed for two weeks at the beginning of March. Track closures will be clearly signposted while these works are taking place, including at the start of affected tracks.

For ongoing updates, visit our Petone to Grenada investigations page.

This map shows the track that will be temporarily closed during the works (in red).

What do these terms mean?

Preferred route

A refinement of the emerging preferred corridor study area following further investigation and design. We will use the preferred route to apply for statutory approvals under the Fast track Approvals Act. It's important to note, there may still be adjustments to the alignment within the preferred route as the design progresses.

Route protection

Route protection is the term we use to summarise all the statutory processes and approvals necessary to protect land for future construction of state highway infrastructure.

Protecting the route gives planning certainty for people, businesses and communities. It supports future planning and ensures the land is available when the project is ready to be built

Proposed designation

The area of land to be designated (protected) to build the project. We are in the route protection phase for Petone to Grenada, therefore we're still some time away from submitting the Notice of Requirement which will authorise the designation.

Have a question?

For more information on the Petone to Grenada project, contact us at petone2grenada@nzta.govt.nz

Visit our website www.nzta.govt.nz/petone2grenada