State Highway 1 south of Wellsford reopened last night after a rockfall on Tuesday forced its closure.
Geotech engineers gave the all-clear for the road through Dome Valley between Wayby Valley Rd and Wilson Rd which is the most direct route between Whangārei and Auckland to re-open.
Motorists were forced to use SH16 for the duration of the road closure.
SH1 on Dome Valley has had two other closures already this year due to slips - one in February after Cyclone Gabrielle that lasted 76 days.
Maintenance crews are building a 40-metre debris wall to prevent future loose material from falling onto the road.
The wall will require 30 piles and will be drilled alongside the section of the road to ensure it is resilient to future weather events.
Nearly $80 million has been spent as part of a safety improvement programme on the notorious Dome Valley section north of Auckland since 2019.
Waka Kotahi regional manager of maintenance and operations Jacqui Hori-Hoult said safety was always the number one priority.
“Over the next few days, our teams will be taking advantage of the closure to improve resilience along this stretch of road, proactively improving stormwater drainage.
“This will help to ensure that when the next weather event hits, this section is able to withstand some of the impacts.
“With school holidays about to begin, we are asking families to allow more time to travel and please follow the official detours if you are heading away.
“Plan ahead, allow extra time for your journey and utilise the Waka Kotahi Journey Planner for the latest information on road closures,” she said.