Lawyer Daniel John noted that Dr. J. Gordon Melton when interviewed by an American newspaper in 1988, had defended groups such as the Peoples Temple which was involved in the Jonestown mass suicide in 1978.
In the Milwaukee Journal report at the time, Dr Melton had said that the mass suicide had been transformed into a "definitive cult horror story" by the media and anti-cult groups.
He was quoted as having said of the Peoples Temple: "This wasn't a cult. This was a respectable, mainline Christian group."
When questioned in court yesterday, he said that he had been quoted correctly.
He also replied that another US-based group, Children of God, was not a cult, although he found the group's teachings of encouraging sexual intercourse and masturbation as forms of worshipping God to be "immoral and distasteful".
He was also reported by the US paper as describing the Peoples Temple as "a congregation in a Christian denomination recognized by the National Council of Churches".
He also said at the time: "Overwhelmingly, so-called cults have a positive impact on people's lives. The worst thing that most of these groups can do is waste your time."
Counsel for the defense noted that Dr Melton had been criticized for being a "cult apologist who has a long association of defending the practices of destructive cults" by another expert quoted in the Milwaukee report.
Dr. Melton also told the court that that Jehovah's Witnesses, a religious group that is banned in Singapore, was not a cult.
He said: "They are obnoxious people, but they are not dangerous. They will not kill anybody."