Published Friday, 28 January 2011
The indecent material was downloaded from a device sneaked into Maghaberry Prison.
An investigation has been launched after the smuggled item was found by police in the cell of a life sentence prisoner last week.
The PSNI was alerted to the situation by prison officers.
Finlay Spratt, chairman of Prison Officers' Association, says it is "nearly impossible" to find every item in searches, but they do their best.
"There are certain limitations that are placed on us, so therefore prisoners have many, many ways of smuggling items on their clothing or even within their body cavities that we can't get to," he said.
"We probably would say 99 times we succeed, but unfortunately there are times we don't succeed."
A statement from the Prison Service said: "As a result of an intelligence led search at Maghaberry, the NI Prison Service called in the police to investigate the inappropriate use of a stand-alone computer at the prison.
"The investigation is ongoing but we can confirm it does involve the alleged downloading of inappropriate images."
Raymond McCartney, Deputy Chair of the Justice Committee, has expressed deep concern and called for the investigation into the matter to be thorough.
"This is a very serious situation and warrants a thorough and speedy investigation by the PSNI. They need to ascertain that these alleged practices are not widespread," the Sinn Féin Foyle MLA said.
He called for the full facts of the incident to be released to the public.
Maghaberry Prison is Northern Ireland's highest security facility, but it has recently been the centre of a number of embarrassing incidents.
These include 'dirty protests' by dissident republican prisoners over their treatment in the jail's Roe House accommodation, and the departure of a newly-appointed governor after just five months due to a security threat.
The initial findings of a major report into failings at the prison, ordered by Justice Minister David Ford, will be published soon.
DUP Assembly Member Paul Givan said this new security breach has raised further questions.
"It's shocking, it shouldn't have happened and now questions need to be asked as to how this device got smuggled into the prison," the Lagan Valley MLA told UTV.
"This is supposed to be Northern Ireland's category A prison, the most secure prison in Northern Ireland - clearly that's not the case, and there's concern that if they can smuggle this in, then what else can be smuggled in?"