Road to Raglan on track to re-open Saturday - Fri 3 March update


Friday 3 March, 8.18pm update: 

State Highway 23 - the road to Raglan -  is now OPEN.

road repaired with new bitumen and markings

This updates the media release below.

Wednesday 1 March, 11.11am

Waka Kotahi NZ Transport Agency advises that the main route to Raglan should reopen to the public on Saturday, in spite of heavy rain affecting road surfacing work earlier this week.

The final pavement work is underway, meaning people will soon be travelling on a two-lane temporary diversion road on private property, which skirts the serious slip that closed State Highway 23.

“We are delighted that this diversion road is almost ready to open, restoring road access for all traffic on this crucial link between Raglan and Hamilton, as we know how important it is to people in this community,” says Cara Lauder, Waka Kotahi System Manager for the Waikato. 

“Our aim is to get this road open by midday Saturday. If we can open it earlier, we will. Road users should keep an eye on the Waka Kotahi Journey Planner and our Facebook page for updates.

“This could not have been done without the generous co-operation of the landowners, or without the herculean efforts of our work team, who put in many long hours to make this solution a reality. 

“Within days of the initial slip, we were able to begin tree felling and the earthworks needed to construct the temporary diversion road,” Ms Lauder says. 

While SH23 was closed, Waka Kotahi contractors Fulton Hogan took the opportunity to bring forward some planned resurfacing work to a steep section of the highway further west. This will be completed in time for the opening of the diversion road, preventing further disruptions for people travelling on the route.

The new temporary road is raised to protect the fibre optic cable running under the site. The cable was not exposed by the slip, and the ground over it was covered with protective metal plates while the tree felling and earthworks were under way. 

The temporary diversion road will open with a speed restriction of 60km/h but will add only minimal extra time to the journey between Raglan and Whatawhata. 

Ms Lauder says that the slump is still active. “It continues to move, and geotechnical testing, including drilling and core penetration, is ongoing. We have not yet got the full picture of how Cyclone Gabrielle has impacted the site, and the ground was already saturated due to the unprecedented rainfall over January.’’ 

The slip significantly worsened after Cyclone Gabrielle; a section of the highway nearly 30m long has dropped around 2.5m, and the slip has crossed over the centreline.

"The temporary diversion road allows us the time we need to thoroughly investigate and plan the long-term restoration of SH23,” Ms Lauder adds.

SH23 between Whatawhata and Raglan was closed on 1 February, after the slip developed on the section known as the Raglan Deviation.

Earthworks on the temporary diversion road were halted on the morning of Sunday 12 February due to a serious incident on a nearby worksite.

Waka Kotahi is deeply saddened by the fatality that resulted. The safety of the people carrying out work on the roads and the safety of all road users are the top priorities when managing traffic through worksites. The site is under full investigation and the matter is with NZ Police and Worksafe.


Monday 30  January: SH23 closed to one lane due to cracking.

Tuesday 31 January: Crack became 300mm drop.

Wednesday 1 February: Drop became slump. Geotechnical assessments underway. Road closed overnight and detour route established.

Thursday 2 February: Road closed to all traffic, while engineers continued to investigate severity of the situation and ongoing risk.

Friday 3 February: Plan actioned to construct a temporary diversion road.

Saturday 4 February: Tree felling began.

Sunday 5 February through to Saturday 11 February: Felling completed and earthworks begin.

Sunday 12 February: Work halted due to a fatal incident on a nearby site, and the impending Cyclone Gabrielle.

Tuesday 14 February: Site re-inspected by geotechnical experts, slump has deepened to 2.5m and is now around 30m long.

Wednesday 15 February: Earthworks and road construction resumes.

For updates and more information: