In the Bible's New Testament, Jesus cast out the Devil from those who were possessed.
Since then, exorcism - banishing the Devil from people or places - has been a part of Christianity and also appears in other religions.
It entered popular culture with the 1970 movie The Exorcist, whichshowed a young girl possessed by demons and the battle of Catholic priests to save her.
The practice traditionally involves prayer and laying on of hands.
In modern times, mainstream churches have concentrated more on emotional healing.
The Catholic Church prints a manual with a sanctioned exorcism rite, the Rituale Romanum, which includes instructions on specific robes to be worn, scriptures to be read and sometimes the laying-on of hands.
Catholic Church representative Lyndsay Freer said the Church believed people and places could be possessed by the Devil - and exorcisms were occasionally carried out in New Zealand.
Each Catholic bishop designates a particular priest to carry out exorcisms. Care is taken to distinguish between the supernatural and mental problems.
An Auckland Anglican minister and lecturer at St John's Theological College, the Rev Dr Peter Davis, said: "The practice of exorcism has not disappeared from the Anglican Church but it would be seen today in the wider context of a healing and pastoral ministry, informed by an understanding of mental health and psychology."
Dr Davis said exorcism was a powerful method of outreach for early Christians when belief in the Devil was almost universal.
Trevor Mander, operations manager for Cultwatch, a Christian ministry to educate people about cults, said: "Extreme Pentecostal churches see demons everywhere."
The practice of casting out demons is not restricted to Christianity.
Other religions such as Judaism, Hinduism, Buddhism and Islam all have some form of traditional exorcism rituals.
