Bosses are cutting down on the type of content employees can access online, according to a web security company.

McAfee found that music download sites such as iTunes and internet dating sites fared the worst with bosses.

A third of the 1,049 respondents said they had blocked such websites and a quarter had stopped their staff from accessing online music communities such as Last FM and video content sites such as Youtube.

Over half of bosses wanted to block social-networking sites such as Facebook or Myspace, but despite security fears only one in five had done so. McAfee said that this was because many companies use this medium for work communication.

This was also the case when it came to instant messaging, with over half of bosses saying they would like to block this medium but were unable to.

Toralv Dirro, McAfee Avert Labs security strategist, said: “The lines between work and play are blurring... but putting fair-usage policies in place and educating people on how to be safe on these sites is the most realistic option.”