The reopening of the Manawatu Gorge road after recent slips has been delayed by newly uncovered structural damage.
The NZ Transport Agency said structural damage to SH3 in the Manawatu Gorge caused by recent slips and heavy rainfall means the road cannot be safely reopened to traffic this week as hoped.
Detailed inspections undertaken by structural engineers before the planned reopening of the highway later this week revealed a concrete retaining wall supporting the road has shifted and must be replaced, Transport Agency highway manager Ross l'Anson said.
The damaged retaining wall on the river side of the road was discovered after slip material was cleared near Kerry's Wall, 4.5km from the Ashhurst turnoff, which has been the site of several slips since the closure of the road on April 24.
"We've looked carefully at the option of opening the road to a single lane while this retaining wall is replaced and the road is repaired, but further heavy rain in the gorge yesterday has made the area more unstable," l'Anson said.
"In its current state the width of usable road surface at this slip site is very narrow. We would need to have vehicles passing directly under the slip while the work is carried out, which would pose unacceptable safety risks for road users.
"We know how frustrating this news will be for people, and we know how vital this route is for the region, but we simply can't reopen the road before it is safe for people to use. We're focused on getting the road reopened as soon as possible, and our crews are working hard to get the job done."
Crews are bringing shipping containers to the slip site to act as a temporary barrier and provide a protection zone for workers who will be replacing the retaining wall.
The timeline for reopening the road to traffic will be determined by how quickly the concrete retaining wall could be replaced, and while the work will be done urgently, the road is likely to remain closed to traffic for another week.
"At this stage the repairs are not expected to be completed before the end of next week, but as soon as the repairs are done it is safe for traffic to use the road it will be reopened, initially to a single lane at the slip sites."
With the Pahiatua track and the Saddle road continuing as the alternative routes while repairs to the gorge road are carried out, motorists are also being reminded to be patient, drive to the conditions and watch their speeds when driving through the communities along the alternate route.