Green light to extend Waikato Expressway to Piarere

Monday, 22 September 2025

Now there’s consent for an extension of the Waikato Expressway to Piarere, Waipā’s mayor is looking forward to seeing shovels in the ground.

NZTA has the tick to extend the Waikato Expressway south to Piarere, though it had to respond to critiques of several aspects of the project.

The plans include an interchange at the State Highway 1 and Karāpiro Rd intersection as well as pedestrian and cyclist access to Karāpiro School.

Consent was granted by an independent panel, the Environmental Protection Authority said.

Local leaders, including the Waipā Mayor, have been pushing for the expressway extension for years.

Mayor Susan O’Regan said the project getting the go-ahead is a good step forward and is looking forward to getting spades in the ground.

Construction is expected to start by the end of next year, NZTA says.

Recent research by AA noted deaths and serious injuries on the Cambridge-Piarere stretch of road had gone up, whereas the numbers were dropping on the expressway.

The research found that SH1 between Cambridge and Piarere saw a 75% rise in deaths and serious injuries over the past two decades.

And an AA rep expects the planned expressway extension to improve traffic flow and reduce crash numbers.

NZTA told an independent panel that the expressway will reduce the injury crash rate by up to 70%, by installing median wire and roadside barriers.

But getting the green light wasn’t easy.

The panel criticised NZTA’s initial ‘trust me’ approach, which had lacked geotechnical data and relied too heavily on management plans to sort out technical risks later.

Mercury Energy, which operates the hydroelectric station at Karāpiro Dam, opposed the project, amid potential impacts on Tunakawa Ridge, where existing drainage and monitoring wells are located.

The panel warned of possible geotechnical risks, such as large earthworks, material disposal, land stability, groundwater drawdown, and settlement.

Waipā Mayor Susan O’Regan says the project going ahead is a good step forward.

It noted the stability effects at the Tunakawa Ridge, noting the serious consequences if dam stability was compromised.

However, Mercury and NZTA agreed to work together during construction to protect the ridge.

The ecological impacts were described as the most “contentious aspect” of the proposal, with the Department of Conservation and councils concerned about losing habitats for birds, lizards, and long-tailed bats.

But the panel said NZTA made an effort to avoid any sensitive areas and that any remaining issues could be managed.

NZTA has five years to begin construction, before the consents expire.

At the moment the Waikato Expressway ends south of Cambridge, where it connects with the existing State Highway 1.

NZTA’s aiming to begin construction by late next year, “subject to a range of supporting activities being completed, including the confirmation of funding,” a spokesperson said.

“This is an important milestone and allows us to proceed to the next stages of planning with certainty, including making decisions on funding, and completing property acquisition and design,” the spokesperson said.

Work is expected to take about 6-7 years.

Trucking Association chief executive David Boyce has welcomed the decision, saying he’s all for building new roads.

“New roads are safer and help get trucks from point A to B. They also help increase New Zealand’s productivity,” Boyce said.

O’Regan said the project’s green light shows that Wellington and NZTA had confidence in the region and were prepared to invest.

“I think a lot of that has come by way of some really improved relationships between Waikato leaders and Wellington.”

In regard to plans to build an interchange at the State Highway 1/Karapiro Rd intersection, O’Regan’s pleased NZTA has provided a way to connect nearby Karāpiro School to the township.

“It’s always a real challenge for Karāpiro School and I’ll continue to advocate for other alternatives for them, in the long term,” she said.

In a brief statement, Transport Minister Chris Bishop said the decision is good news.

AA’s Waikato District Council chair Bill McMaster said crashes often happen because people have to adjust from driving on a four-lane highway to a two-lane road.

He said the extension to Piarere would make traffic flow better, since traffic is equally split, heading towards the Bay of Plenty and south to Tīrau.

“The whole upper North Island being linked by the ports and a lot of heavy vehicle movement, will make a massive difference to the overall efficiency, safety and comfort of drivers travelling on that route,” McMaster said.