Nearly one-third of British companies are now blocking access to social networking websites, such as Facebook and Twitter, at work, according to a survey.
In 2010, only 9 per cent of British companies had bans on social networking sites in place, compared to 32 per cent now, The Telegraph reports.
According to Clearswift, the security firm that carried out the survey, some 53 per cent of managers are now concerned about employees using social networking websites at work.
The survey said that a series of high-profile hacking incidents, such as the recent attacks on Sony, has driven concern among managers that employees could leak data or be tricked into downloading computer viruses.
Earlier this year, Sony was forced to shut down its PlayStation Network for weeks after hackers gained access to users' personal data, and the incident is eventually expected to cost Sony hundreds of millions of dollars, the paper said.
However, increased restrictions could cause tensions, particularly between employers and younger staff.
According to the survey, 55 per cent of people in the age group of 18 to 24 see social networking as an "entitlement", while the figure is 37 per cent for 45 to 54-year-olds.
Clearswift said that employees expected access to social networking in return for agreeing to modern working practices, such as working from home, out-of-hours, or during their commute.