Exorcism is no fantasy according to the church, with the Sydney archdiocese last month appointing an as-yet unnamed priest, suitably ''endowed with piety, knowledge, prudence and integrity of life'' to conduct exorcisms, as required by Catholic canon law.

In Rome, the Vatican is preparing its first official English translation of the rite of exorcism, which was promulgated in 1614 and reissued in 1999. Its chief exorcist, Father Gabriele Amorth, claimed this month to have carried out 70,000 exorcisms. Bishop Porteous - who has stood in as exorcist for the Sydney archdiocese over the past five years - warns that yoga, reiki massages and tai chi can lead to people being in the grip of ''demonic forces''.

''A person can move from the use of a simple practice to de-stress to embracing the underlining theory and religious beliefs because these all come out of religious traditions of the East and people can then find themselves in the grip of demonic forces,'' he said. ''People can be naive in that regard.''

But David Tacey, associate professor of English at La Trobe University, said demonic possession was an archaism long discredited by science, psychology and modern theology. Any suggestion that reiki massage, yoga and tai chi could have evil influence were ''expressions of Western ignorance about Eastern practices'', he said.

''This is an example of how certain voices in the church have no idea about other cultures and religions,'' Professor Tacey said.