THE next time you see an employee hunched intently over the computer, don't imagine he or she is slaving over the office accounts or a report for the next shareholders meeting.

Employees are more likely to be whiling away the hours on the social networking site Facebook, a report says.

Richard Cullen of SurfControl, an internet filtering company, estimates the site may be costing Australian businesses $5 billion a year. "Our analysis shows that Facebook is the new, and costly, time-waster," he said.