The Knights Point slip, 27km north of Haast, occurred during heavy rain in October 2012. It begins 5m from the edge of SH6, and runs from the road to the sea 250m below.
At the Queenstown Lakes District Council's full meeting in Wanaka yesterday, councillor Leigh Overton raised concerns about the instability of the slip site, concerns he said were shared by West Coast residents.
The council should be working closely with NZTA to assess the degree of risk, given the impact further deterioration of the slip could have on access to the Queenstown Lakes district, Cr Overton said.
In a statement to the Otago Daily Times, NZTA Christchurch highway manager Colin Knaggs said in the event of further deterioration at the site which placed access along the road at risk, an anchored pile wall would be built along the seaward side of SH6.
A decision was made in August to design the wall, which would take one to three months to build and cost up to $2 million.
NZTA had been monitoring the site weekly, but there had been no further movement of the slip despite the area experiencing its worst winter weather in years, Mr Knaggs said.
Lake Wanaka Tourism general manager James Helmore said his organisation was concerned about the Knights Point slip in light of the impact road closures at the Diana Falls slip in the Haast Pass were having on Wanaka visitor numbers.
''There are some immediate actions we are taking in terms of educating the Auckland/Wellington travel trade as to viable alternative experiences the Lake Wanaka region offers - glaciers, beech forest, scenic flights etc, talking with relevant businesses to create new products to take advantage of potential demand, and ensuring visitors continue to travel within the Lake Wanaka region to Lake Hawea and Makarora.''
