Students occupying the dining hall of Trinity College Dublin, have accused the university of escalating the situation.
They say security has now locked around 60 protesters into the room, leaving them without food or access to toilet facilities.
It is reported they are being allowed to leave but cannot re-enter the dining hall.
The students are protesting against the introduction of a fee of €450 for students who need to repeat their exams.
Shane Collins is the president of the Graduate Students Union at Trinity, he says they are very concerned.
He said: "There is no access to food in here, supplies are an issue.
"Depending on how long they are going to continue what they have implemented so far, we could be here for hours or we could be here for days."
However, Trinity College has denied the claims.
In a statement the college said:
"However, we are not letting anyone else into the building, as there were concerns that large numbers of non-students had been invited into the building through an open call, and this would result in unacceptable risks for all concerned.”
- Digital Desk