The number of assaults in Oberstown Children's Detention Centre in Dublin increased by 18% last year.
There were 32 in 2019 and 27 the year before, according to new Freedom of Information figures.
Last year, there were 15 assaults by a child on a staff member and 17 child-on-child attacks.
However John Lonergan, a former governor of Mountjoy Prison and Tipperary native, said it is not a big concern.
Mr Lonergan said: "That would strike me as low, very predictable, 15 over a year is a little over one a month of some type of aggressive behaviour between a member of staff and a boy or a girl.
"That, in my view from experience of working with young people way back in the 70s and 80s, would be to be expected because, naturally, they wouldn't be in detention if they weren't presenting with some sort of behaviour difficulties or challenges."
