Rescuers working in sub-zero temperatures were unable to begin searching the wreckage because the site remained dangerously unstable, nor could helicopters get into the area because of the icy conditions.
One of the lodges contained staff workers in the popular alpine resort in the Snowy Mountains, about 250 miles south-west of Sydney, which is usually packed with skiers and holiday-makers for the middle of the Australian winter. There was no immediate explanation for the slide in a region which has always been renowned as geologically stable.
"There are early suggestions that we have about 18-20 people that have not been accounted for," said a Sydney police spokesman last night.
"The site instability is hampering the rescue operation. It's very unstable unfortunately."
Local police said it appeared several dozen people had been injured but the exact number and the extent of their injuries was not known.
There were early media reports that some people had been killed. Police could not confirm this, although one senior officer said it was almost certain that people had died.
"It is my belief that it's highly likely that we will have a number of fatalities," Superintendent Charlie Sanderson said.
Supt Sanderson said snow expected in the area later today could further hamper rescue operations.
Tourists from nearby lodges said they head voices crying from the rubble as they tried to find survivors before police halted rescue efforts over safety concerns.
"We got down into the rubble as soon as we'd evacuated families and children," said Glenn Milne, a journalist who was holidaying at Thredbo.
"We heard three voices, three separate voices," he said."When the rescue services arrived, they judged the situation simply to be too dangerous and told us we had to get out of there."
One of the workers who escaped said: "I was tucked up in bed at 11.30 asleep. I heard a sound like a strong wind. I looked out the window and saw rubble. This was no wind. I ran for my life to find company."
One of the first emergency workers on the scene said: "This is the last thing you would think would happen here. There have been only light snowfalls in the valley and maybe two days of rain in the past month. There's no explanation for this.
"To see all this rubble and the lodges and cars piled up, it looked like a tornado had gone through the area. There are mangled parts of buildings and huge concrete slabs. It's so unstable."
Emergency rescue crews flew in by helicopter from Sydney, Melbourne and Canberra, the capital, but their initial efforts were hampered by darkness and fears that the fragile rubble could slip further. About six people who escaped from the two lodges were taken to a nearby hospital.
Witnesses said the scene was a jumble of debris and wreckage. They said earth slid about 100 metres down a hill, dumping one lodge on top of the second.
One witness said: "It looks like someone has taken a great big bulldozer and just drove over both the lodges and they just slid down the hill."Reuse content