The Australian Broadcasting Corp. reported Valeska Paris said the church's leader, David Miscavige, sent her to the cruise ship The Freewinds when she was 17 to stop her mother from taking her away from Scientology.
The broadcaster said she was born into a Scientology family in Switzerland and at age 6, moved to the church's headquarters in the United Kingdom, where she was placed in its youth wing, then joined its Sea Organization at 14, ABC said.
"I was basically hauled in and told that my mum had attacked the church and that I needed to disconnect from her because she was suppressive," Paris said.
Her mother had criticized Scientology on French TV after her ex-husband committed suicide, ABC said.
The Freewinds cruises around the Caribbean and docks at small islands.
"They take your passport when you go on the ship and you're in the middle of an island," Paris said. "So it's a bit hard [to escape] and by that time I was 18, I'd been in Scientology my whole life. It's not like I knew how to escape."
Paris left the Freewinds when she was sent to the Rehabilitation Project Force in Sydney, described by Scientologists as a voluntary religious retreat and by detractors as a punitive re-education camp, ABC said. At the camp, she met former St. George Rugby League champion Chris Guider, then married him and left the church.
In a statement, the Church of Scientology denied Paris' claim she was held against her will.