The Transport Agency says it will work around the clock to reopen the Milford Road as soon as possible after a slip brought down hundreds of tonnes of rocks on the tourist route.
The only accommodation provider at Milford Sound says many customers can't get to the settlement and it's costing the business thousands of dollars.
Milford Sound Lodge manager Jupke Doodeman says the only way in and out of Milford is by air or sea until the road is restored and a handful of people are stuck there and have opted to extend their stay.
However, she says the lodge has taken a financial blow - missing out on about 30 customers a night and having to give refunds to people who had already booked.
Ms Doodeman says several customers have been airlifted out of Milford leaving behind rental cars.
A cruise company says the rock fall will be expensive for businesses in Milford Sound.
Real Journeys had to fly out some of its customers on Saturday who had been on a cruise.
Chief executive Richard Lauder said there have already been 10 two-day closures on Milford Road this winter.
Although companies are used to the closures, Mr Lauder said this time it will have quite an impact on their revenue.
He said the four cruise operators in the area will suffer until the road is re-opened.
NZTA hopes to reopen one lane by Wednesday
New Zealand Transport Agency (NZTA) says it will work around the clock to try to open the Milford Road.
Some of the boulders on the tourist route to Milford Sound are in excess of 200 tonnes.
NZTA Southland manager Peter Robinson says workers have started to remove smaller debris so they can start breaking down the larger boulders.
He says whether or not the road can be opened by Wednesday depends on how easy it is to break down the big boulders which have dropped 500 to 900 metres down the slope.
Mr Robinson says the road surface has been damaged but gravel will be laid so vehicles can use the road.
NZTA closed the Milford Road at 4pm on Friday in case of avalanches.