Govt Advances SH1 Wellington Improvements with Expanded Infrastructure Plan

Second Mt Victoria Tunnel, Terrace Tunnel, and Basin Reserve Upgrades to Ease Congestion and Boost Economy.

The NZ Transport Agency (NZTA) Board has approved the next steps for the SH1 Wellington Improvements Road of National Significance (RoNS), an expanded infrastructure project designed to tackle congestion and fuel economic growth, Transport Minister Simeon Brown announced.

“Our Government is committed to building a second Mt Victoria Tunnel to alleviate Wellington’s traffic congestion and support economic expansion. I’m pleased to see the NZTA Board taking this next step, which includes a duplicate Terrace Tunnel that will further improve connectivity and efficiency for commuters and freight,” Minister Brown stated.

SH1, Wellington’s main arterial route, is heavily congested, especially during peak hours, with projections showing a significant population increase in the region that could worsen travel times without major improvements. Without intervention, travel times between Ngauranga and the Airport could rise by 50 percent within the next decade.

Expanded RoNS Package: Key Components

The endorsed plan includes:

Second Mt Victoria Tunnel

A parallel tunnel to alleviate bottlenecks and improve travel flow.

Duplicate Terrace Tunnel

Designed to further reduce congestion along SH1 and improve accessibility.

Basin Reserve Upgrades

Enhanced traffic flow to support North-South bus corridors and commuter routes.

“These upgrades promise substantial time savings during peak travel periods, including up to 10 minutes for trips between the northern suburbs, the CBD, hospital, and airport,” Minister Brown said.

For public transit commuters, benefits will also be significant: morning peak travel times on the number one bus between Island Bay and the Railway Station will decrease by approximately 9 minutes, while those on the number two bus from Miramar to the CBD are expected to save around 11 minutes.

Project Delivery Timeline and Economic Impact

The SH1 Wellington Improvements will be implemented as a single corridor project, though the construction will be staged. After a detailed investment case, the NZTA Board is expected to make final decisions by mid-2025.

Minister Brown expressed confidence that the chosen option will meet Wellington’s evolving transportation needs: “The RoNS projects previously completed by National have proven highly successful in easing congestion and improving safety on State Highways. Moving quickly to develop this new generation of RoNS projects is a clear signal of our Government’s focus on prioritizing investments that provide measurable value to commuters and businesses.”

The SH1 Wellington Improvements are a critical part of the Government’s overall plan to rebuild the economy, create jobs, and enhance productivity by ensuring reliable transport networks across New Zealand.