The show's winner: Richard Hatch on the island

The network said in a statement: "We heard about Stacey Stillman's allegations several months ago.

"They had no merit then. They have no merit now that she has packaged them into a frivolous and groundless lawsuit."

Survivor, based on a British format devised in the 1980s, pitted two "tribes" against each other on an island off the coast of Borneo. Each week, one of the tribes voted off a member.

Ms Stillman was the third contestant to be evicted from the island.

She is claiming damages for alleged fraud, breach of contract and unlawful business practises. Fellow contestants Dirk Been and Sean Kenniff are also accused of conspiracy.

Mr Kenniff said he did not feel coerced, while a spokesman for Mr Been declined to comment.

Ms Stillman has also asked for compensation to cover lost prize money, plus $75,000 (�51,540) in damages.

Hatch took away a $1m prize

Rudy Boesch made it to the final four contestants on Survivor, but the competition was won by corporate trainer Richard Hatch, who received $1m (�687,380).

The series was the most successful summer prime-time show in US TV history, with almost 60 million viewers tuning into the show's final episode.

A British version is being developed for ITV by production company Planet 24, under the control of Nigel Lythgoe, the LWT executive behind the success of Popstars.