Almost 10 per cent of surveillance incidences relating to the Regin computer spy bug were in Ireland, the fourth-highest of any country in the world, after Russia, Saudi Arabia and Iran.

The bug, which was uncovered by US technology company Symantec, has been described as one of the most sophisticated pieces of malicious software ever seen. But why was Ireland targeted and should we be worried?

Andy Harbison, IT forensic lead at Grant Thornton, says Ireland was likely a target of the computer spying bug due to the presence of so many large multinationals here.

However, he says we should not be worried, as the surveillance bug was governmental. He said it was possible to tell the malware was being funded by a government in the western world, due to the language used in it, the fact that it is well looked after and that it is after the wrong information to be criminal.

Harbison believes it may have been targeting a US company here or someone’s data which is being stored in Ireland.

Symantec's security operations manager Orla Cox said several computers in one Irish company were infected by the bug, which is a highly targeted threat, designed to go unnoticed for a long time.

She also said the level of skill and time required to develop such a sophisticated bug means it was most likely funded by a nation state.

It is likely the bug’s development took months, if not years, to complete, and its low-key nature means it can potentially be used in espionage campaigns lasting several years.

Even when its presence is detected, it is very difficult to ascertain what it is doing.

The first incarnation of the bug was used to spy on a number of organisations from 2008 to 2011, when it was “abruptly withdrawn”, according to Symantec. A new version then showed up last year.