More than half (54 percent) of IT managers believe employees should be banned from watching the World Cup using their PC at work, says Blue Coat Systems.
Research by the network management firm revealed that 69 percent of IT managers were convinced their office staff would be determined to watch the England matches during the tournament.
This could lead companies to find their corporate bandwidth fully occupied by video streaming, slowing down networks and potentially causing them to crash.
Furthermore nearly two thirds (65 percent) of UK firms have no policies in place to prevent office networks being used to stream live broadcasts, such as football matches. And 64 percent said they had no rules to govern the use of social networks including Facebook and Twitter during office hours.
However, 80 percent of businesses admitted they did have clear guidelines governing access to non-business websites.
Nearly three in five (59 percent) firms do not have technology installed that will prioritise vital business applications and ensure the most efficient delivery of video streaming, either.
"Many employees are unaware of the effect of running video streaming on a network, and this is the first World Cup where so many online options exist to follow the games and also interact on social networking sites with friends and colleagues," said Nigel Hawthorn from Blue Coat Systems.
"As a streamed football match consumes around 750MB of bandwidth - the equivalent of sending more than twelve editions of Tolstoy's War & Peace – it's important that IT and HR managers clearly communicate their corporate rules to employees."
Blue Coat System's research comes as ISP Eclipse revealed more than half of all office workers admitted they were planning to watch matches online during working hours.
See also: Sony to film World Cup in 3D