Haast and Makarora business owners are reporting ''huge'' losses in revenue as a result of the major slip on State Highway 6, between the Gates of Haast Bridge and Haast Pass Summit.
Heavy rain frustrated efforts by the New Zealand Transport Agency to reopen State Highway 6 yesterday, forcing the closure of the road until at least tomorrow.
The slip at Diana Falls has blocked the highway since last Wednesday and is having a significant impact on tourism businesses on either side.
Eamonnd Johnston, co-owner of Johnston Motors, at Haast Junction, said the shop and petrol station side of his business had been ''dramatically'' affected by the road closure. Sales were down as much as 90%.
Haast's Fantail Cafe closed its doors from Friday until Sunday because of a lack of patrons, only opening again yesterday when it was thought the road would reopen.
''It's just gone dead for us. Our business completely revolves around the tourists,'' cafe co-owner Janene McIntyre said.
She said the lack of cellphone coverage in Haast further compounded the situation for motorists, a view shared by Wilderness Accommodation owner Ollie White.
Guest numbers at Mr White's motel and backpacker business were down at least 50% since last week's slip.
Simon Jackson, general manager of the Heartland World Heritage Hotel, at Haast Junction, said few tourists were willing to wait it out in Haast for the road to reopen.
''After a day, people turn around because most of the people have limited time. They have to be in Queenstown the following day so a lot of people have taken the long route [through Arthurs Pass].''
Many whitebaiters - who generated considerable revenue for the hotel - had left Haast before last week's storm and were now unable to return, while several group bookings had been cancelled as a result of the road closure, Mr Jackson said.
Business owners on the other side of the slip are also suffering.
Makarora Tourist Centre manager Michelle St John said the road closure had been ''absolutely devastating'' for all aspects of the business.
Although tourist numbers were always lower at this time of year, whitebaiters typically kept the centre busy. However, since the road closure, business had dropped to ''about a tenth'' of its usual level.
Staff at the centre dealt with ''chaotic'' scenes yesterday morning as they assisted with the travel plans of up to 30 carloads of people who waited several hours for the road to open as expected before having to turn back, Ms St John said.
Lake Wanaka Tourism general manager James Helmore said while it was fortunate the road closure occurred in Wanaka's shoulder season, he expected it would still have a negative effect on the town's business operators.
''Conversely, there will be people travelling up the West Coast who are staying in Wanaka a bit longer.''
NZTA West Coast area manager Mark Pinner said unexpected heavy rain on Sunday night destabilised the slip site again and brought new debris down, making it unsafe for contractors.
''With further bad weather forecast for Wednesday, it has developed into a bit of [a] day-to-day situation at the moment.''