The Prison Service director Sue McAllister has asked for an updated assessment of the current security threat to her staff in the wake of last week's bomb attack on a prison officer.
The revelation was made by the Justice Minister David Ford in the assembly.
The 52-year-old officer suffered serious injuries when a bomb exploded under his van on Friday morning.
A dissident republican group calling itself the IRA said it was responsible for the attack in east Belfast.
The group, which is widely referred to as the new IRA, said he was targeted for training officers at Maghaberry Prison near Lisburn in County Antrim.
The prison officer is in a stable condition in hospital.
MLAs from all sides condemned the attack at the start of assembly proceedings on Monday.
The DUP's Paul Givan said the attack was part of a campaign by republican dissidents to get the regime in Maghaberry Prison returned to the old days of the Maze jail.
The Ulster Unionist Andy Allen, who was seriously injured in a bomb attack while on duty with the army in Afghanistan, assured the injured officer that "there is a light at the end of the tunnel".
The SDLP leader Colum Eastwood said the prison officer was a public servant who should not have to expect that a bomb might be placed under his car.
Mr Eastwood described the dissident strategy as nonsensical.
Sinn Féin's Raymond McCartney, a former IRA prisoner, said those responsible for the attack have little or no support in the community.