A sensible security approach is needed to tackle the risks created by employees using social networking sites at work, a major trade union has stressed.

According to the TUC the best policy is for employers to set out a clear code of conduct for using the internet, explaining what risks are presented and how employees can avoid them.

By taking this consultative approach the union believes employers can minimise the potential for virus attacks on workplace PCs and commercially sensitive information being leaked, without generating disquiet in the workplace through a heavy handed ban on certain websites.

"Simply cracking down on use of new web tools like Facebook is not a sensible solution to a problem, which is only going to get bigger," said TUC general secretary Brendan Barber.

"It's unreasonable for employers to try to stop their staff from having a life outside work, just because they can't get their heads around the technology.

"Better to invest a little time in working out sensible conduct guidelines, so that there don't need to be any nasty surprises for staff or employers," he added.

The union also warns that employers must explain if they expect employees not to discuss particular work matters online, as otherwise unnecessary disciplinary actions could follow.