Opponents of a big motorway scheme near Wellington packed a High Court gallery in the capital on Wednesday to hear their lawyers challenge the project.
The New Zealand Transport Agency had hoped to begin work in July on the Kapiti Expressway, a 16km, four-lane highway that would bypass Paraparaumu and Waikanae town centres.
The $630 million road was approved by a board of inquiry three months ago, but Mark Harris of protest group Save Kapiti said on Wednesday it is taking court action to stop it.
"What it would do (is it) would split the district in half. It will have a motorway basically in between parts of the suburbs - and that's just not acceptable urban planning. It's bad urban design, it's bad transport planning and we've had to stand against it all the way."
The scheme has been supported by the Government, which made the entire route between Levin and Wellington airport a Road of National Significance.
But the group's lawyer Richard Fowler, QC, told the court the approval for the project was based on wrong analysis of its benefits. Mr Fowler said it relied on 65-year-old plan to build a road through the Kapiti sandhills, which was not a sound basis for approving a four-lane highway now.
Mr Fowler said a previous incarnation of this transport proposal - the much smaller Western Link Road - had been proposed and approved. It was in the District Plan and had even been partially funded.
Mr Fowler said this gave it statutory protection, made it official and on the record, and this meant it couldn't be simply discarded. He said there was no legal right for the Board of Inquiry to press "an exit button" and replace that proposal with something much bigger and substantially different.
Another complainant, Marie O'Sullivan of the group Alliance for a Sustainable Kapiti, told the court the Board of Inquiry had been legally required to consider the impact of the motorway on the environment and local amenities. However, she said it didn't do so, except in a very generalised way.
The plan is strongly supported by the Government which views the main road from Levin to Wellington airport as a Road of National Significance.
Lawyer Helen Andrews spoke on behalf of the Board of Inquiry. She argued that the Western Link Road might have been a designated road and might have been in the District Plan, but that did not mean it would necessarily be built and, therefore, would not necessarily be in a position to be protected from a new proposal such as the motorway.
Ms Andrews made it plain that the motorway would consign the Western Link Road to history since it would follow the same path in many areas and so could not co-exist with it.
John Hassan represented the New Zealand Transport Agency and told the court it was required to do "real world" analysis, without "artificial assumptions" about the environment to be protected.
By that he meant the Western Link Road hadn't yet been built and therefore was not part of the environment and couldn't really be capable of being protected by a court order at this stage.
Justice Gendall reserved his decision.
