An increasing number of companies are banning their workers from accessing social networking sites, it has been suggested.

According to figures produced by MessageLab, nearly 20 per cent of firms now restrict the use of such sites among employees, partly due to concerns over security.

Security analyst with MessageLabs Paul Wood stated that social networking sites can present a danger to companies if staff go on to pages which contain malicious code.

He stated: "Organisations need to raise awareness about the risks of these sites. Some of the policies are not up-to-date."

Research released last year by Dimension Data indicated that businesses in the UK are taking an increasingly sophisticated approach to dealing with staff internet use, with rising numbers of organisations implementing selected as opposed to outright bans of worker access to the web.

According to the Alastair Broom from Dimension Data, such an approach can lead to enhanced employee morale.