In comments that may shock some staunch Catholics, Cardinal George Pell has described the biblical story of Adam and Eve as a myth.

He appeared alongside renowned evolutionary biologist and atheist, Professor Richard Dawkins, on the ABC's Q&A program last night.

Cardinal Pell said the existence of Adam and Eve was not a matter of science but rather a mythological account.

"It's a very sophisticated mythology to try to explain the evil and the suffering in the world," he said.

"It's a religious story told for religious purposes."

According to Genesis, God created Adam and Eve as the first man and woman and all people are descended from them.

Cardinal Pell's explosive comments came after he was questioned about evolution.

He said it was impossible to say when there was a first human.

It is widely accepted in the scientific community that life on Earth has evolved over about four billion years.