He said Benedict, regarded as a staunch conservative during his time in office, had "allowed exorcists to administer the sacrament of exorcism not only to people who are suffering from demonic possession, but also those who suffer other evil disorders, such as diabolical infestations."
Fr Amorth, the Catholic Church's best known exorcist, will be a special guest on Friday on a television programme to commemorate Benedict's papacy. The programme, to be broadcast on a religious satellite channel, will be called: "Joseph Ratzinger and the Devil - the history of a pontificate and the battle against evil".
Fr Amorth, the exorcist for the diocese of Rome, is a controversial figure whose outspoken views have embarrassed the Vatican in the past.
In the past he has branded yoga as "evil", claiming that it leads to a worship of Hinduism and other Eastern religions based on "a false belief in reincarnation".
He has also railed against Harry Potter, saying the children's books seem innocuous but in fact encourage children to believe in black magic and wizardry.
He claimed in a book last year that Pope Benedict unwittingly performed an exorcism of two men possessed by the Devil in the very heart of the Vatican, describing how he and two assistants brought a pair of "possessed" Italian men to one of the Pope's weekly audiences in St Peter's Square in May 2009.