More than 2,000 police officers, soldiers, politicians and prison officers were warned their personal details were "compromised" by the alleged Stormont spy ring, the Government has revealed.
Security Minister Paul Goggins has revealed the details of 2,195 people were stolen before the 'Stormontgate' spying scandal was exposed.
These included the details of 77 PSNI or Garda officers, 1,583 prison officers, 13 army personnel and 37 politicians.
Mr Goggins revealed the figures in a parliamentary written answer following a question by DUP Upper Bann MP David Simpson.
The minister declined to state whether every individual was told by police that their details had been stolen.
He said: "The decision was taken at a senior level in the PSNI as to which individuals should be notified, in the context of the contents of the material obtained, and taking security and human rights considerations into account."
He also declined a request by Mr Simpson to detail how many of those whose details were stolen were members of Loyal Orders.
In February, Northern Ireland Secretary of State Peter Hain stated that £30m had to be spent on protective measures following the leaks.
However, in his written answer, Mr Goggins appeared to suggest the total security costs were not yet fully known.
He said: "A full investigation into the total cost of ensuring the safety of all the individuals concerned would be complex and wide-ranging.
"Such an investigation could not be conducted without incurring disproportionate cost."
Three men were arrested after a police raid on Sinn Fein's offices in Parliament Buildings in October 2002, which led to the collapse of the power-sharing Executive and Assembly.
Last December, the Public Prosecution Service dropped spy-ring charges against 55-year-old Sinn Fein official Denis Donaldson and two other men on the grounds it would not be in the "public interest" to proceed. Donaldson was later found shot dead following a break-in at a remote cottage near the village of Glenties, Co Donegal, after admitting being recruited in the 1980s as a paid British agent.