State Highway 6 south of Murchison will reopen to a single lane tomorrow morning, three days after it was closed due to major rockfall.
Photo: Supplied / Waka Kotahi
Waka Kotahi systems manager top of the south, Andrew James said it was likely tree roots and water ingress into the fractured cliff face caused massive boulders to fall on the road.
It has left further fractured rocks overhanging the cliff face at risk of falling.
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James said temporary protection will be in place to allow people to use the road safely.
"Contractors have been building a stone-filled container wall in the northbound lane to protect the existing road shoulder. This means all traffic will be able to move through the section of road while work continues to stabilise the rockface."
A permanent fix will take some time and only a single lane will be available initially.
"Our engineers are still working through what the solution will be, and this will take time to get right. Currently, we can't give a timeframe for reinstating the road to two lanes, but we do want to achieve this as quickly as possible."
James said the safety of workers and road users at the rockfall site was a top priority.
"We must do everything we can to make the road safe. The huge size of the boulders that came down earlier this week graphically demonstrates the potential risk to road users."
Work at the existing underslip, 150 metres west of Dellows Bluff, continues. The goal was to have this project finished by the end of the year.
The road re-opening comes in time for returning school holiday traffic.