Theresa May has faced calls to establish an independent public inquiry to examine a now-closed detention centre that was described as a "living hell" for young prisoners.
Labour's Laura Pidcock said rape and torture were "commonplace" at Medomsley Detention Centre, but many of the victims are not covered by the wider Independent Inquiry into Child Sexual Abuse due to their age.
The MP for North West Durham suggested a separate investigation to secure justice for them.
Prime Minister Mrs May expressed surprise at Ms Pidcock's remarks and pledged to examine the issue.
Durham Police have carried out an investigation involving 1,800 witnesses into what happened at the centre, near Consett, County Durham, from its opening in the 1960s to its closure in 1988.
It was built on the site of a Victorian orphanage and was designed to house young offenders aged 17 to 21 to serve sentences for offences which today would not routinely attract a custodial sentence.
Inmates would normally spend six to eight weeks at the Home Office-run centre before being released.
Speaking at Prime Minister's Questions, Ms Pidcock said: "Medomsley Detention Centre in my constituency was a living hell for the boys and young men sent there from across the UK in the '70s and '80s. Rape and torture were commonplace.
"So far 1,800 men have bravely come forward to say they were affected. Some of those young men reported that abuse decades before the first person was convicted for some of those crimes committed.
"Nearly a year ago I met with the Home Secretary, along with a victim of abuse at Medomsley, to make the case for a public inquiry.
"Many of the victims are not covered by the inquiry into child sexual abuse because of their age. We need to know what happened at Medomsley, we need justice for survivors, and we need to make sure it never happens again.
"Will the Prime Minister please say we can have an independent public inquiry into the abuse at Medomsley Detention Centre?"
Mrs May replied: "I take very seriously the issue she has raised and what happened at the Medomsley Detention Centre.
"First of all, the independent inquiry into child abuse is looking into historic cases of abuse in institutions, in state institutions, and they're doing that on a step-by-step basis in the areas they're looking at.
"But I will look at the issue - I was surprised at the statement she made that the Medomsley Detention Centre cases weren't able to be covered by that inquiry and I will certainly look at that issue."