Redford founded the Sundance festival

The festival, being held in Utah, has a reputation for launching independent films into the mainstream.

"Once the festival achieved a certain level of notoriety, then people began to come here with agendas that were not the same as ours," Redford said.

"We can't do anything about that. We can't control that."

The 11-day festival opened on Thursday with the premiere of Friends with Money, a dark comedy starring Jennifer Aniston.

Blurred lines

Sundance has proved a successful springboard for small budget movies that have gone on to be box office hits, including The Blair Witch Project, Super-Size Me and Reservoir Dogs.

Because of their success the big movie studios began to take notice and began holding parties and deal-making meetings on the fringes.

"Sometimes it blurred what we are doing," said Redford.

"Sundance is about storytelling. Storytellers can broaden our minds: engage, provoke, inspire, and ultimately, connect us."

He added: "We have been fortunate to work with artists who embody the independent spirit and we're grateful to them for sharing their original stories and diverse voices."

There will be 64 films competing for prizes in the US, international and documentary categories.

Stars expected to attend screenings of their independently-made films including Robert Downey Jr, Maggie Gyllenhaal and Paul Giamatti.