Waka Kotahi NZTA says it's too early to say what impact lockdown will have on the already troubled Transmission Gully motorway being built north of Wellington.
The $1.25 billion road is due to open on September 27 following budget blowouts, delays, and bailouts.
It's becoming clear the final hurdle is less likely to be physically building the road on time as it will be getting signoff on 41 outstanding tasks needed to meet environmental consent conditions.
Greater Wellington Regional Council, the regulator, has recently raised a red flag saying there's a risk the project's partners will not meet these requirements for the road to legally open on the agreed date.
Transmission Gully project spokeswoman Natasha Utting told the Herald construction was now 98 per cent complete.
In the process of building the road 11.4 million cubic metres of earth has been excavated and more than 115,000 tonnes of asphalt laid.
The current focus, while the country is in Covid-19 alert level 4 lockdown, is on essential activities, Utting said.
This includes protection of works, safety, security, and environmental protection on site.
Meanwhile, the majority of road barriers have been installed. Just before lockdown road signs were being put up, major sign gantries installed and line marking put on the road.
"We've still got some sealing to finish on some of the road surface, and other finishing touches and 'road furniture' to install," Utting said.
The next step to get Transmission Gully open will be the overall commissioning of the road, which involves a range of tests like checking the radar system.
This system will eventually be able to detect incidents like stopped vehicles, cars going the wrong way, or animals or debris on the road.
Transmission Gully is the first motorway in New Zealand to use this technology.
Before the 27km motorway can be safely and legally opened, construction teams need to ensure that safety, quality and environmental requirements have been checked and met, Utting said.
"These checks are an important part of protecting people using the road and the environment surrounding it."
Over the course of construction about 7700 people have worked on site.
Utting said Transmission Gully performed extremely well in weather that battered the region on Monday night.
Motorists faced significant delays on State Highway 1 at Paekākāriki after a slip blocked the southbound lane. Queues were backed up on the road in both directions.
Debris that had fallen on to the railway lines also caused a passenger train to derail in the area.
Utting said the slip on SH1 demonstrated just how vulnerable the coastal route was.
"The Transmission Gully motorway is designed to be a safer and more reliable route for freight and private vehicles than the current route.
"The motorway will provide the Wellington region with greater resilience in natural disasters; providing an alternative route that is better able to resist and recover from earthquakes and storms."
After last year's five-week nationwide lockdown, the builder of Transmission Gully got
$145.5 million from Waka Kotahi to cover the costs of delays.
The final $7.5m will only be paid if the road opens by the agreed date.
On top of that, the builder will be liable for $250,000-a-day in damages if the road doesn't open on time.
A Waka Kotahi spokesperson said it was too early to say what impact the latest Covid-19 alert level 4 lockdown would have on Transmission Gully.
"Waka Kotahi will be working closely with Wellington Gateway Partnership and the builder, whose immediate focus is on securing essential worker permits to ensure safety, security and environmental protection on site."
This year the transport agency has brought in additional experts, including an independent chairperson, in the race to get outstanding resource consent requirements signed off for the road to open on time.
Greater Wellington Regional Council chairman Daran Ponter has said he's "nervous" about whether the 41 tasks could be signed off for the road to open on September 27.
A council spokesman said desktop analysis, which will be used for the majority of the current tasks, can continue without interruption during lockdown.
"However, if alert level 4 does continue this could potentially delay any required site visits."
Once the motorway is open to traffic, there will be another six months of work to fully complete the project.
This includes finishing the landscaping, and integrating the Intelligent Transport System with the wider network.