At least four Limerick prison officers have taken legal advice over the discovery that prisoners at the jail had access to staff personnel files.
The Prison Officers Association (POA) has asked for an independent investigation into the incident, following the transfer of a computer holding the sensitive information from the prison governor's office to the prisoner's library.
A spokesman for the Department of Justice confirmed the computer had been moved last month. He said it had not been switched on when it was moved into the library on June 18th.
"On Wednesday it was turned on, two prison staff had access to it, and they saw information relating to prison staff."
Two prisoners had been in the library at the time. "They were asked by the governor if they had seen information on the computer and they said they hadn't."
Solicitors for four of the prison officers have written demanding that each of their clients be shown the information on their files. This information has been given to them, the spokesman said, and any other officer who asked would be given their own file.
A senior POA source said home addresses were not believed to have been on the files.
It is believed that Department officials have found information relating to up to 30 officers on the computer, and the records of all the prison officers, some 150 people, could have been held on it.
"Some of the information would have been detailed information in relation to work records, like doctors' reports in relation to officers who were sick," the POA source said.
The POA is due to meet officials from the Department of Justice on Monday, to discuss overcrowding in Mountjoy Prison in Dublin.
The population there has exceeded 700 since the beginning of the year. The prison was designed to hold 547 prisoners, but has a maximum bed capacity of 670, using bunk beds in cells that were built as single cells.
Yesterday, there were 748 prisoners in Mountjoy, a slight drop from the figure during the worst overcrowding in March.
The high numbers in Mountjoy are reflected elsewhere in the prison system. Yesterday, the authorities recorded more than 2,660 prisoners in custody, one of the highest numbers ever.
