Key Points:

An evangelical Christian ministry accused of using exorcisms and prayer to treat young women with mental illnesses or eating disorders is operating a clinic in Auckland.

New Zealand women have also attended the Mercy Ministries clinic in Sydney, where the rituals are said to have been held.

Three of its former Australian residents went public this week, saying they were left "broken or suicidal" after Mercy staff repeatedly told them they were possessed by demons and that Satan controlled them.

They said "exorcisms" were used to treat their conditions, which included bipolar and anxiety disorders and anorexia.

Little or no medical or psychological services were provided; instead, those who broke the rules were disciplined, and girls who became friends in the clinic were subjected to "separation contracts".

But a New Zealand woman this week rejected these claims, saying she had met many other Australians and New Zealanders who had successfully been through the Mercy programme.

"It is a Christian organisation and the girls are aware of that when they apply," she said. "I think the term exorcism is far too strong. Most Christians would be familiar with standing around and praying while placing a hand on someone's shoulder."

Mercy opened a clinic on a $1.5 million property in Albany in August and its first intake of eight residents are still to "graduate".

The Gloria Jean's cafe chain supports it with fundraising and promotion.

Mercy's New Zealand website says it is part of a worldwide network that provides a "structured residential programme" for women aged between 16 and 28 who face issues such as abuse, depression, eating disorders and unplanned pregnancy.

It issued a statement saying the programme was designed "to equip them with life principles, social skills, training in nutrition and fitness and offers counselling and health advice".

Its only New Zealand trustee is Maree De Jong, senior pastor at the Life church with her husband Paul De Jong.

Its application form asks about involvement in same-sex relationships or "spiritual" pursuits such as Dungeons and Dragons.