The daughter of the president of the Church of Scientology in Australia has spoken out against the organisation, describing it as toxic and accusing the church of tearing some families apart.

In an exclusive interview on ABC 1's Lateline, Scarlett Hanna has detailed life growing up in the former Cadet Org: a group set up for the children of Scientology's elite unit, the Sea Org.

"The best way I can describe it is cattle," Ms Hanna said of their treatment. We were property of the organisation."

Ms Hanna is the only child of Vicki Dunstan, president of the Church of Scientology in Australia, and Mark Hanna, a former Asian/Pacific director of public affairs for the church.

She claims children of Sea Org members rarely had contact with their parents, lived in separate homes and were granted only 20 minutes each night with their parents.

"I can't describe it. It was just an incredibly lonely childhood. I had no-one to talk to or to look after to me, or to ask me how I was after school or any of those things that most of us take for granted," Ms Hanna told ABC 1's Lateline.

Sarah McClintock, a current member of the Sea Org, grew up with Ms Hanna and rejects the allegations.

"What she is saying I did not experience. I don't know where she is coming from with such things. It really doesn't make any sense to me because I grew up with her. I was there with her and I think people are giving her things to say," she said.

Sheila Huber, a former Sea Org member, says she witnessed poor treatment of children at the Church of Scientology in Los Angeles.

Ms Huber, a former executive establishment officer for the organisation, cared for children in the Cadet Org when she was 16 years old.

'Terrified of sunlight'

She says she looked after around 30 infants all crammed into a one-bedroom apartment.

Ms Huber claims the children were only allowed outside once in eight months and they were terrified by the experience.

"They spent so much time in their cribs, day after day, night after night, that they wouldn't go in any space larger than the size of their cribs. They were terrified. They were terrified of the sunlight," she said.

Ms Hanna says the Department of Community Services in New South Wales twice visited Cadet Org homes when she was a child.

"The furniture was dismantled by a division within the Sea Org that deals with labour and the kids were sent out for the day so it would appear they were living according to crowding laws," she said.

Ms McClintock says she has no recollection of this occurring.

Ms Hanna says the worst part of her experience was the separation from her parents.

Her father Mark Hanna was sent to the Church of Scientology's rehabilitation unit, the RPF, in the United States when she was a child.

"He was gone for several years probably two or three years," Ms Hanna said.

"I lost my father. I had no-one to talk to - it was very humiliating."

Virginia Stewart from the Church of Scientology in Sydney denies the church routinely separates family members.

"I don't actually agree it's been routinely done and I think in that instance in that family you would have to speak to the father and the mother about why they lived like that, why they chose to take that action," she said.

But Ms Huber, who spent a year separated from her five-year-old boy while in the RPF, says she had little choice.

"I got surrounded by eight grown men, grown Sea Org members, and in a circle around me, telling me I am now going to the RPF," she said.

Ms Hanna says she decided to speak out following the screening of a Four Corners story on Scientology on ABC1 earlier this year.

"I just think the church needs to take some accountability for what it was involved in, maybe apologise to some of these people that have had such traumatising experiences," she said.

The Cadet Org no longer exists in the Church of Scientology. Ms Hanna's parents declined to be interviewed by Lateline.