One of Australia's best-known sceptics has signed a pact with the Devil.

The president of the Australian Sceptics Society, Mr Barry Williams, signed the pact in front of more than 250 people at the society's recent national convention in Melbourne.

Mr Williams was presented with the contract by a researcher into the paranormal, Mr Drew Sinton.

Mr Sinton challenged other members of the audience, which included parliamentarian Mr Barry Jones and magician Mr James Randi, to sign the pact.

Mr Williams had now become a "guinea-pig", Mr Sinton said, who would be watched by the sceptics to see what happened.

Mr Sinton said he presented the contracts to see if members of the sceptics' society were more superstitious than they would admit.

He said it was significant that most people, including Melbourne University's head of earth sciences, Professor Ian Plimer, would not sign the pact, which was based on a 16th century contract

The contract ends "I do hereby sacrifice my soul, my self and my companion unto thee, to do as thou wilt. As soon as thou wilt."

"They made sport of me, but the fact remains that they didn't sign it," Mr Sinton said.

"So what were they afraid of?"

He said Mr Williams was now caught in a "catch 22" situation, where anything bad that happened to him could be put down to the contract.

However, to get out of the contract, Mr Williams would have to renounce it in public, thereby admitting his belief in the supernatural, Mr Sinton said.