The SH6 Haast Pass route remains closed due to destructive flooding and massive amounts of slip material.
The highway between the South Island's west coast and Otago is staying closed over the weekend to allow the removal of material on either side of Muddy Creek Bridge.
Waka Kotahi NZ Transport Agency said the SH6 route has been closed since Thursday morning's torrential rain.
"An overflow of spill north of Makarora flooded the highway for up to a kilometre at Muddy Creek," Waka Kotahi's system manager for southland Robert Choveaux said.
"We estimate at least 20,000 cubic metres of material will be trucked from the highway to stockpile points before we can fully re-open this highway."
He said the material on the bridge is up to four metres deep and combined with the snow in recent days, has turned "concrete-like".
No shortcuts from Haast to Queenstown and central Otago
As a result, people in South Westland can expect a journey of more than nine hours to get to Queenstown via SH6 to the north, SH73 Arthur's Pass and the southern highways from Christchurch.
"We understand the inconvenience this represents for hospitality providers in South Westland and Queenstown Lakes District, particularly at the start of the school holidays," he said.
He said crews are working hard in a "restricted, narrow strip of road" to get the section of Haast Pass back to two lanes and to have normal services restored within the next week.
"Both West Coast and central Otago highway maintenance crews have been working at the site, with the Otago Aspiring Highways crew," he said.
"Machinery operators on two excavators, two loaders, five trucks and a bulldozer are continuing to make inroads to the material on the highway to get to the bridge deck itself.
"It is a huge job."
The next update on alternative routes or the highway opening is expected around midday on Monday 25 September.
