Gardaí are investigating a security breach at the recruitment website RecruitIreland.com.
It is thought that names and e-mail addresses of those registered with the site were accessed for spamming purposes. The site was shut down yesterday afternoon when the breach was noticed.
Gardaí and the Data Protection Commissioner have been informed.
CVs, usernames and passwords are not thought to have been compromised.
In a statement, the company said it was taking the incident very seriously. It warned users not to reply to any spam email or comply with any requests for information such as bank account details.
Dermot Williams of IT security company Threatscape said hackers are displaying remarkable commercial ingenuity by targeting less well guarded systems they can make a lot of money from.
"This is only the latest in a continuing series of cyber attacks where you might be puzzled as to why an attacker targeted what seems to be a non-obvious and 'unprofitable' target," he said.
"But when you take a closer look you realise that in all these cases there is the potential for an attacker to generate monetary gain by harvesting email addresses to populate a lucrative spam database.”
