A prisoner has been released in error - the third such incident involving the Northern Ireland Prison Service in the space of two months.
Sean Gerard Cahill was convicted of aggravated vehicle taking at Belfast's Laganside Courts last Wednesday and sentenced to a month's imprisonment.
He was released because of the time he spent on remand awaiting trial but should have been returned to custody to face charges of robbery, possession of an offensive weapon and taking a vehicle without the owner's consent.
Justice Minister David Ford said: "I have demanded that a disciplinary investigation be launched immediately into this most serious matter. It is vital that we urgently find out why this has happened and if individuals are to blame I will move swiftly to take the appropriate action."
This is the third time within months that a prisoner has been released in error.
A prisoner who was wrongly released after appearing in court in Downpatrick in October has been arrested.
Connelly James Cummins, 25, was detained by police in the Elgin Street area of south Belfast.
Cummins had been due to stand trial for theft, aggravated vehicle taking and using a vehicle without insurance. He was released in error at Downpatrick Magistrates' Court on 1 October, even though his file was marked "hold" as he still faced other charges.
He was the second prisoner to be mistakenly released by the Northern Ireland Prison Service in a matter of days.
Alleged rapist Devidas Paliutis was freed from Maghaberry prison.
Mr Ford has begun a disciplinary investigation into the latest lapse.
"This is the third time in a matter of months that a prisoner has been released in error and I share the public anger that will naturally follow this latest serious incident," he added.
SDLP justice spokesman Alban Maginness said the Prison Service needed to seriously tighten up its procedures.
"These series of mistakes suggest systemic failings rather than a series of accidental errors," he said.
"The minister needs to take effective action to remedy this."
DUP chairman of the Assembly Justice Committee Lord Morrow said the announcement of a third wrongful release was absolutely scandalous.
"There is something very wrong when prisoners are released by accident in this way," he said.
"To lose one prisoner might be regarded as unfortunate but to release three in the space of two months is nothing short of scandalous.
"David Ford has announced that there will be an immediate inquiry. I welcome that, but any inquiry must report back within a matter of days rather than weeks or months in order to restore public confidence. If there are systemic problems here, it is vital that the minister moves quickly to take necessary corrective measures."
Sinn Fein vice-chair of the committee Raymond McCartney said the incident pointed towards a culture of complacency that must be addressed to restore public confidence.
"There is a degree of disbelief that we have had two high-profile cases recently surrounding the release of prisoners and now we are dealing with a third, all within two months," he said.
"The Criminal Justice Inspectorate were asked to carry out an investigation as to how these two previous cases occurred. We were led to believe that this would bring an end to these type of incidents.
"However, this has obviously been repeated and we will be seeking assurances from the Minister that some action will now be taken to ensure this cannot be allowed to happen again.
"Alongside this, there is also the concern that this incident took place last Wednesday, yet we have only heard about it six days later. There is an apparent culture of complacency which has arisen that must be addressed in the strongest possible sense in order to restore public confidence."
Ulster Unionist justice spokesman David McNarry said he was extremely concerned at the latest incident.
"I am deeply concerned at this latest development and I know these concerns will be shared by the general public who will simply not understand how this could happen so soon after the promises made in the aftermath of the last incident," he said.
"It is getting beyond a joke, and it is clear to me that the Justice Minister needs to get a grip on some of his officials and impress upon them that their primary concern is to protect the public and instil confidence in the justice system. So far they are failing miserably in this regard."