The inability of the historical institutional abuse inquiry to examine the claims of certain victims threatens to create a "justice gap" in Northern Ireland, campaigners have warned.
Amnesty International has highlighted the plight of women who suffered mistreatment in Magdalene laundry-style workhouses north of the border.
While such institutions are covered by the terms of the inquiry, the state investigation can only hear the allegations of those who were under 18 at the time of their stay, as it is limited to probing the experiences of children.
Thousands of women who attended the Catholic-run workhouses in the Republic of Ireland received a state apology for their treatment earlier this week after an official report highlighted the shocking conditions they endured.
Patricia Campbell from Amnesty said she welcomed the establishment of the abuse inquiry in Northern Ireland, but called for its remit to be extended. She said: "The terms of this inquiry look at the abuse suffered by children in institutions in Northern Ireland.
"We're concerned about the experiences of young women in Magdalene Laundries in Northern Ireland, because young women who were abused in these organisations over the age of 18 aren't covered by the terms of the inquiry. We've written to Office of First and Deputy First Minister pointing out this justice gap.
"Amnesty International would like to see what they're going to do in order to remedy it, because it seems wrong to us that women who suffered this abuse in the Republic of Ireland are going to receive redress and an apology, but not women in Northern Ireland."
Inquiry chairman Sir Anthony Hart said the probe's terms of reference were not within his control. He said: "The question of the remit is a matter ultimately for the First Minister (Peter Robinson) and the deputy First Minister (Martin McGuinness) and for the Assembly.
"Now the Assembly has passed a special act to allow this inquiry to take place and our terms of reference are limited by that. If our terms of reference were to be expanded it would be a different inquiry, it would be much more complicated and inevitably it would take much longer."
The inquiry's remit also does not cover mainstream primary or secondary schools or allegations of clerical abuse committed outside of residential facilities.