Auckland councillor Chirs Darby says a legal challenge against the $1.4 billion Mill Rd project by climate change advocates All Aboard Aotearoa is a sign of what's to come.
The group applied for a judicial review of the Waka Kotahi NZTA led project in the Wellington High Court on Thursday.
The 21.5km proposed Mill Rd arterial route, which would provide an alternative road between Manukau and Drury, would run parallel to and to the east of State Highway 1. Construction was expected to start next year and be completed by 2028.
All Aboard Aotearoa is a coalition made up of Generation Zero, Lawyers for Climate Action, Bike Auckland, Women in Urbanism, Movement and Greenpeace and its stated goal is to decarbonise the country's transport by 2030.
Generation Zero campaigner Dewy Sacayan said its followers had fought long and hard to see the Zero Carbon Act come to fruition.
"This is the year we enforce it and hold the Government to account. The Government simply cannot say it is taking the climate emergency seriously and then fund roading projects like Mill Road," Sacayan said.
Lawyers for Climate Action's Jenny Cooper said with nine years left to halve New Zealand emissions as required under the Paris Agreement and Zero Carbon Act, the Government must stop building and financing more roads.
"Every policy, project and funding decision is crucial in ensuring a fair future for generations to come. Allowing the status quo - climate inaction - is in fact direct action towards an unsustainable future in which our children face severe environmental degradation and exponentially rising costs," Cooper said.
Darby said he wasn't surprised by the challenge and said people needed to realise climate change wasn't just about political rhetoric.
"I think it's something we're going to see more of," Darby said. "Advocates like this aren't just going to write letters anymore, they will take action."
He said the group appeared before Auckland Council's planning committee last month and talked about its goal of decarbonising the country's transport by 2030.
"I wouldn't say they threatened legal action, but they were direct about how they reserved the right to legally challenge projects and programmes that didn't meet the council's climate change objectives.
"It's something I'm aware of. Politicians have made some strong statements about the issue. Our prime minister said climate change is this generation's nuclear free moment and we will as a country tackle it head on."
Darby said both central and local government had to back up the commitments that they've made on climate change.
But he said a project such as Mill Rd was only encouraging more urban sprawl and higher emissions.
Matt Lowrie, editor of transport and urban design blog Greater Auckland, said he wasn't surprised to hear about All Aboard Aotearoa's legal action.
He said there had been a number of recent cases internationally against projects on the grounds that they will have a negative impact on carbon emissions and climate change.
Lowrie said that included a legal challenge by Friends of the Earth against plans to expand Heathrow Airport in the UK.
"I think Mill Road is a project that needs to be challenged. There are already rumours it will cost a lot more than previous estimates," Lowrie said.
He said the money earmarked for Mill Rd would be better spent on other more important projects.
"Otherwise it will just encourage people in those areas to continue to be auto dependent and lead to more emissions and more congestion."
In response to questions about All Aboard Aotearoa's legal action, Transport Minister Michael Wood said it would be inappropriate to comment on a matter before the courts.
"However, our Government has committed to climate action. We've declared a climate emergency, made climate change a key priority for transport projects going forward and committed to policies to reduce transport emissions like the Clean Car Import Standard.
"Given transport makes up 47 per cent of NZ's CO2 emissions, we know we have to do more and I'll be making further announcements in the coming months."
Auckland Mayor Phil Goff said the project was fully funded by the Government as part of the NZ Upgrade Programme and is designed to address population growth and safety issues in southern and eastern Auckland.
"However, it is not a substitute for the need to use mode change and a more compact urban form which are both priorities for Auckland Council, and into which billions of dollars is being invested under the Auckland Transport Alignment Programme."