There is concern that those exploited are not seen as human trafficking victims
The Immigrant Council of Ireland has launched the first ever research report on sham marriages in Europe.
It finds that women taken to Ireland are closely monitored and kept isolated, with little linguistic knowledge.
The report defines these arrangements as marriages between EU and non-EU nationals for the purpose of immigration advantage "where exploitation of one or both parties has occurred."
But the council has expressed concern that those exploited in sham marriage situations are not defined as victims of human trafficking.
According to the report, this is an emerging form of human exploitation in Europe - and there are many common features between victims of exploitative sham marriages and victims of human trafficking.
Dr Monica O'Connor, co-author of the research, says: "When the women arrived in Ireland, they were brought to accommodation which in many cases housed a number of men.
"They were closely monitored and kept isolated in a foreign country with little knowledge of the local language.
"In many cases, the women had their papers taken, their movements were tightly controlled, and they had little or no access to the outside world.
"Women reported multiple forms of exploitation - most commonly sexual assault, rape and physical abuse - by individuals or several perpetrators that lasted several weeks, months or years."
The report finds there is also evidence of deception and control; movement across borders; physical and psychological abuse - as well as incidents of rape, sexual abuse and enforced domestic servitude.
The project is supported by the European Commission's Prevention of and Fight Against Crime Programme, and involves Latvia, Lithuania, Estonia, Finland and Slovakia, and Ireland.
Nusha Yonkova, Anti-Trafficking Manager with the Immigrant Council and co-author of the research report, says the victims of exploitative sham marriages are typically women from Eastern European countries.
"These are young and very vulnerable girls, coming from extremely impoverished backgrounds," she says.
"Several common risk factors for victims were identified during the research project, including teenage pregnancy and a background of domestic violence, neglect, sexual abuse, and foster or institutional care at a young age.
"Family breakdown and extreme poverty were also among the main risk factors.
"The majority of women had little education and had no workable knowledge of English. All of the women had some pre-existing connection with their recruiter, who was a family member, a friend or a friend of the family from their country of origin."
CEO of the Immigrant Council of Ireland, Brian Killoran, told High Noon here on Newstalk more needs to be done by the State.