The Prison Service has strongly rejected suggestions that prisoners at Maghaberry Prison are subject to 23-hour lock-up.
A protest by 28 dissident republican inmates at the Co Antrim high security jail ended on Monday evening after the dining room in which they had barricaded themselves was stormed.
A group linked to the Continuity IRA has said the protest was over prison conditions, including lock-downs.
Sinn Fein has also criticised the Prison Service over its treatment of dissident inmates.
North Belfast MLA Caral Ni Chuilin claimed inmates had been denied the right to wear Easter lillies outside their cells.
Ms Ni Chuilin, a former prisoner herself during the Troubles, said: "Regardless of why anyone is in prison they are entitled to be treated with respect and dignity.
"It is clear that the regime in place for republican prisoners in Maghaberry falls well short of this."
However, a spokeswoman for Prison Service said: "The allegation that prisoners in Roe House are locked in cells as standard practise for up to 23 hours is not true.
She added: "Prisoners are free to wear lilies at Easter in their own cell or in the recreation room, but not in the communal areas.
"The Prison Service's policy on a harmonious environment has been upheld in the courts. The same restriction applies to the wearing of orange lilies in July."
© UTV News