Work to clear dangerously large and unstable rocks high above State Highway 6 restarted on Friday morning after rain made conditions treacherous.
Torrential rain last weekend caused flooding, slips and closed roads, including the Epitaph Slip that cut highway access between Haast and Lake Moeraki.
State Highway 6, north of Lake Moeraki and from Haast south remains open for business, but there is no available detour with motorists being told to consider using the Arthur's or Lewis passes.
The New Zealand Transport Agency said it would provide a further update including a definitive timeframe for reopening the road on Wednesday or earlier if possible.
But a spokesperson said crews were forced to stop rock scaling work north of Haast on Thursday when heavy rain started to fall.
Tuesday after the first day of scaling/rock removal at the Epitaph rift, showing why people cannot be on the road while work is underway given the distance the rocks travel, bouncing over the highway into the bush. Photo: NZ Transport Agency / Waka Kotahi
They had been working on the cliff face since Tuesday after sorting out a helipad to deliver equipment.
Rock scaling work has been progressing well since it restarted on Friday morning, but that work and road repairs could continue over the weekend, the agency said.
"Following the completion of rock-scaling, crews will clear rockfall material and construct a bund to protect the road. The bund to protect the road, recycling fallen rock, can only be built once the rockfall risk from above is cleared enough for the crews on the ground to be safe."
The section of highway between Lake Moeraki to Paringa fully reopened on Friday, but motorists should prepare for delays as work to clear slips continued.
"NZTA understands the importance of this key route to the region, and work is being completed as quickly as possible to safely re-open the road."
This week, crews have been filling cracks in the highway, using airbags to release unstable rocks above the road, clearing overhanging vegetation - including using explosive to look at rocks and assess their stability, and starting drainage work.
"The protective bund design and its alignment next to the highway has been approved so crews are ready to install it once it is safe to do so," the agency said.
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