The inquiry, which is set to get under way later this year, will look at allegations of abuse relating to children in residential care, including independent boarding schools.
But it will not examine allegations where the child was living with its family or an adoptive family, or where the child was attending a “faith-based organisations on a day-to-day basis”.
Survivors are due to meet their legal advisers amid concerns the inquiry will exclude those abused by members of the clergy, but not residing in an institution at the time.
The Scottish Government said the inquiry had to have a “clear remit” if it was to conclude in the four-year time period.
Alan Draper, a spokesman for In Care Abuse Survivors (Incas), said: “We have some major concerns about how the inquiry is going to work in practice. I think they have let the churches off the hook again and that is worrying. What we wanted was any organisation that had a duty of care to be included, and that would have included churches and the Scout organisation. A priest in a parish who abused ten children is not included.”
Mr Draper said there were also doubts among some abuse survivors about the inquiry chair, Susan O’Brien QC.
He added: “The government said the inquiry must have the confidence of survivors. At the moment, we’re not sure. It’s a name that came out of the blue. We’ve looked at some of the stuff she’s done and it’s not bad, but you have to ask why they picked a QC and not a judge.”
Labour’s education spokesman, Iain Gray, said: “I can understand that the SNP government are concerned about an inquiry remit which is so wide that it will take forever, but this is our one chance to ensure that survivors feel the crimes committed against them are being listened to.
“Survivors’ trust in this process is the thing which will make or break it. If the inquiry is not going to look at abuse which occurred outside of residential settings, then survivors must be convinced that the new Police Scotland unit will investigate these historic crimes.”
A Scottish Government spokeswoman said: “This will be one of the widest-ranging public inquiries that Scotland has ever seen. The initial call was for an inquiry into the abuse of children in institutional care.
“We have listened carefully to survivors of abuse and responded to their request for the scope to be widened. That’s why the inquiry will now consider the abuse of children in a wide range of care settings. But clearly if the inquiry is to succeed and reach clear conclusions it needs to focus on a clear remit within a set time frame.”