Irish websites are not immune to attack, and several high-profile companies have been hacked, cracked or data-bombed. Specialists say no computer system is completely hack-proof, and predict that as more and more business here go online, the level of both security and of attempted break-ins will rise.

In recent weeks, Eircom, 98 FM, the University of Limerick and others have been "cracked" - the main pages of the sites were replaced by messages by the crackers, and signed with nicknames.

Industry insiders view this form of disruption - as distinct from the malicious destruction of entire computer systems - as little more than electronic vandalism.

Mr John McCormac, the editor of Irish technology news site hackwatch.com, predicts that cracking and hacking will grow with e-business.

"As more computers appear on the Net, the chances [of being hacked will] increase. And as technology advances, so will the knowledge of crackers and hackers," he says.

Within the industry, most suspect that some of the most damaging hacks are concealed by the companies involved. For example, the damage to the reputation of a bank whose computer system had been broken into would be seriously undermined if the knowledge became public.

Some companies concerned about their security actually hire former hackers to break into their systems, exposing all the weaknesses that could be used by other hackers.