The South Westland section of State Highway between Haast and Knights Point is likely to remain closed until later this week as crews work to clear debris and assess damage caused by heavy rainfall.

NZTA South Island Central Region System Manager Mark Pinner said a preliminary assessment had been completed, and work would begin on Monday to clear rockfall and conduct ongoing monitoring.

“We have completed a preliminary assessment and works will start on Monday, clearing rockfall and monitoring. In the next 48 hours, we will know more to confirm the programme for the days ahead,” Pinner said.

More than half a metre of rainfall in a 24-hour period over the weekend led to flooding, slips, and cracking along parts of the highway. A major underslip, named the Epitaph Slip, caused further damage to the road surface at Knights Point, with visible cracking.

Pinner outlined two key areas of concern: “Two significant issues are at play here – the cracking in the road at the southern end of the site and the rockfall above the road at the northern end. These are in two different places, but very close together.”

At the southern end, the Epitaph Slip has caused 150mm of road slumping with surface cracks, while the northern end sees a greater risk of rockfall, with about 200 cubic metres of rock sliding down from a gully above the road.

A rock scaling crew, which had been working nearby, will set up on site Monday to assist with the rockfall removal. “Our contractor will begin removing the rocks at the northern end of the rockfall,” said Pinner, estimating this work could take up to three days.

The road surface cracking has not visibly changed since Saturday night, Pinner added, though NZTA will know more within the next 48 hours as monitoring continues. “While the rock pile is being removed and the higher up rocks are scaled off the site to the north, we will continue to measure and monitor the cracks in the highway,” he said.

Remedial work to stabilise the site will include repairs at road level where recent movement caused damage and drainage repairs to reduce further slope instability.

Efforts to clear the highway have already allowed some limited access. A track-level route north of Lake Moeraki enabled an escorted convoy of visitors to safely exit on Sunday afternoon with the assistance of Civil Defence.

NZTA said SH6 between Fox Glacier and Lake Moeraki is likely to reopen to the public on Monday.

“We understand that this is an essential lifeline and tourist highway for the wider West Coast, Queenstown Lakes, and Central Otago districts,” said Pinner. “We are doing our best to re-establish the link around Knights Point as soon as it is safe to do so.”

The goal is to allow single-lane access during daylight hours, extending to full access once geotechnical advisors confirm the road’s stability.

All other roads in the West Coast region remain open, with Hokitika, Greymouth, and the Buller District continuing normal business operations.

For those needing to reach Greymouth or Hokitika, NZTA recommended using alternative routes via Arthur’s Pass or the Lewis Pass from the east coast.