Almost half of all web traffic originating from corporate networks is non-productive, it was claimed today.

Nearly 50 per cent of the web traffic monitored by security firm ScanSafe in February was non-work related, including requests for gambling, music, pornography and webmail sites.

Overall, web filtering blocks were up eight per cent compared to January, according to the firm.

"Beyond the negative impact on productivity, uncontrolled use of the web can have serious and costly consequences for businesses of all sizes," said Dan Nadir, vice president of product strategy at ScanSafe.

"This includes exposure to legal liability, disclosure of confidential information, breaches of compliance requirements and unnecessary bandwidth consumption."

Nadir added that events such as Valentine's Day, the Super Bowl, the Fifa World Cup and the Grand National tend to drive unproductive workplace web traffic.

Prior to the opening weekend of the World Cup, ScanSafe reported an average 147 per cent increase in visits to World Cup-related sites.

The firm also blocked 24 new instant messaging threats in February, 54 per cent of which affected MSN Messenger, 21 per cent Yahoo Messenger and 17 per cent AOL Instant Messenger.

ScanSafe reported a marginal decline in malware in February. Web viruses remained virtually unchanged after increasing 27 per cent in January.

Spyware and adware blocks decreased two per cent in February compared to a 26 per cent increase the previous month.

"Historically, we see a jump in web malware in January followed by a slight drop in February," said Nadir.

"Attackers know that malware may have a better chance of being propagated following the New Year when many users are returning from the holiday and have not patched their PCs.

"This seasonality usually corrects itself and we tend to see a steady increase in malware, particularly spyware, as the year progresses."