New video from the collapsed State Highway 25A site in Coromandel shows the extent of the damage to what Waka Kotahi calls a “vital transport link”.

Work has begun to fully assess the extent of the damage to the highway after it collapsed following the recent heavy rain.

Coromandel MP Scott Simpson posted a video from the site on social media today.

“It’s far bigger than it was yesterday and is still moving. The scale of repair job is going to be enormous,” the post said.

A heavy rain watch is in place for the Coromandel today as well as a severe thunderstorm watch.

Waka Kotahi NZ Transport Agency said it had begun the work needed to get a clear picture of the full extent of the slip damage on SH25A, the first step in planning a solution to restore this vital transport link for the region.

“The damage to the road is significant, the repair will be a huge piece of work,” Waka Kotahi regional transport systems manager Cara Lauder said.

State Highway 25A collapse.

“Waka Kotahi is gearing up now so we’ll be ready to take action as soon as the storm has passed. Our immediate priority is still the emergency response, and the site is still extremely wet and highly unstable.

• Thames-Coromandel Mayor on the extensive road closures and flood damages
• Watch live: 'Be vigilant' warning: Slips close BOP highway, Tamaki Dr feeder road in Auckland

 “As soon as the weather eases, the ground stops moving and it’s safe for our contractors to get back on site, we’ll carry out a thorough geotechnical investigation which will give us the information we need to determine the best long-term fix for the site.

In order to commence work on site as soon as conditions permit safe access, Waka Kotahi has begun engaging specialist contractors and geotechnical engineers, as well as local maintenance contractors who will clear material and develop a safe temporary access track to allow people and machinery to access the site.

Initial on-site work is likely to include drilling boreholes and excavating test pits to understand the strength and stability of the underlying foundation at the site and in the surrounding area.

Lauder said that, provided the weather and ground conditions allowed safe access to the site, Waka Kotahi expected to have initial information on the next steps in the repair and restoration of SH25A to share with the public and stakeholders next week.

“We know how vital this transport link is for the region, and we understand that people are hungry for information and want to know when the road could potentially re-open.

“We’re committed to sharing information as soon as we have more certainty on the way forward, and Waka Kotahi will engage with the public and stakeholders throughout the process of investigation, design and construction of a solution to re-establish a safe and resilient SH25A route for the region.”

State Highway 2 through Karangahake Gorge is reduced to one lane following the large slip near Crown Hill Rd.

The road is under traffic management and motorists are advised to take extra care through the area and expect delays, Waka Kotahi NZ Transport Agency said today.

Footage has emerged of a hillside turning into a river of debris and trees blocking major North Island roads.

A fresh orange heavy rain warning is issued for the district from 11am Thursday to 8am Friday.

The warning is in place for the Bay of Plenty west of about Kawerau, including the Rotorua Lakes District, Western Bay of Plenty District and Tauranga City.

Rain with heavy falls is expected. 70 to 90mm could accumulate with peak intensities of 10 to 20 mm per hour. A heavy rain watch is also in place for the Hunua Ranges and Coromandel Peninsula from noon Thursday to 6am Friday and Bay of Plenty about and east of Kawerau from 11am Thursday and 8am Friday.