By Caroline Briggs BBC News entertainment reporter

The violence in the film shocked preview audiences

Wolf Creek will get its world premiere next week at the festival in Utah.

The movie, which cost £570,000 to make (AUS $1.4m), has already been snapped up by a US distributor in a £1.88m (US $3.5m) deal.

It will also compete in the World Cinema Competition at Sundance which runs until from 20 to 30 January.

Written and directed by Australian Greg McLean, Wolf Creek tells the chilling story of three backpackers travelling in the remote outback.

We still don't know to this day how we managed to do it for $1.4m David Lightfoot, producer

They are thrown into danger when they accept help from a local who turns out to be anything but friendly.

The film has been described as extremely violent even before the final cut has been released, with some people at the test screening fainting from the gore.

The Sundance website says Wolf Creek "is sure to do for Australian horror films what The Texas Chain Saw Massacre did for the American genre".

Producer David Lightfoot told the BBC News website that the reaction of the audience during a test screening last year had been "amazing".

"We had a couple of people who literally fainted in the audience," he said.

"Another couple of people went outside and hid in the toilets for a while before coming back in to see what happened.

Robert Redford founded the Festival over 20 years ago

"I produced this film and I can't even watch it myself."

He added that while the film was not a slasher movie, the secret of its triumph lay in its jolting realism and it packed a psychological punch.

"There are three or four sequences that are very confrontational," Mr Lightfoot said.

"The man is a deranged psychopath - an evil version of Crocodile Dundee - who thinks he is killing vermin. It plays on every primal fear.

"It is the fear of where you are, the massive scale of the outback and the fact there is nowhere to run to."

Parallels have been drawn between Wolf Creek and two notorious crimes in the Australian outback - the disappearance of British backpacker Peter Falconio and the crimes of serial killer Ivan Milat.

Mr Falconio, 28, vanished during an ambush north of Alice Springs in July 2001 while Milat murdered seven backpackers in 1992-1993 in New South Wales.

Film showcase

But while Mr McClean has been reported as saying he drew inspiration from the two grisly crimes, Mr Lightfoot said it was not that specific.

"Greg wrote the original script years ago. He just got to thinking about the number of people who have gone missing in the outback over the years and what must have happened to them.

"I think the Falconio case has left a nasty taste in the mouths of people in this country, but we were already well involved in the film during the time he went missing."

While the Sundance Film Festival acts as an important showcase for new films, Wolf Creek was snapped up by Dimension Films - the genre arm of Miramax Films - after seeing some footage and a rough edit of the film.

Mr Lightfoot said they knew they had a good film on their hands, but did not realise just how good until Dimension doled out $3.5m for the distribution rights in North America, Latin America (except Brazil), Spain, South Africa, Australia and New Zealand.

Traditional style

The deal was sealed on Christmas Eve and both Mr Lightfoot and Mr McClean had the "very difficult" job of keeping keep quiet for 10 days before it could be announced to the world.

And while Mr Lightfoot welcomes the inevitable comparisons between Wolf Creek and fellow Sundance success stories The Blair Witch Project and Open Water, he said there are significant differences.

"Both Open Water and Blair Witch did very well, which is great," he said.

"But the difference with our film is that it was made my professional filmmakers - and that is not to take anything away from the other two.

"Also, the approach of the film is very traditional, unlike the documentary style of Blair Witch and Open Water."

He added: "We still don't know to this day how we managed to do it for $1.4m."