Employers are being urged not to make sweeping changes to staff guidelines stopping employees using the internet without carefully considering regulations.

The warning comes from Birmingham-based solicitor, The Wilkes Partnership, as UK businesses sought to limit social networking sites such as Facebook and MSN.

The moves have come in the face of employer concerns over productivity and IT security.

A survey by online security firm, Surf-Control, found companies were losing an estimated £2 billion through poor productivity. The figure was calculated by looking at the theoretical cost if an employee in every company spent an hour on Facebook each day.

Organisations and businesses, including county councils and NHS Trusts, have implemented total bans, but Wilkes is concerned employers might not be following the correct procedures when making changes to their IT policy and could even be infringing human rights.

"It's perfectly acceptable for employers to make changes to IT usage to stop employees using certain websites if they feel it's in the interests of productivity, but it's important they communicate these changes to their staff, particularly if they intend to police such restrictions by monitoring staff internet use," saids Nigel Wood, senior partner at Wilkes.

"In a case earlier this year, an employer was found to be breaching the human rights of one of its employees by monitoring personal communications without informing the staff member that it would be doing so. A judge ruled that this was an infringement of human rights, which set an important precedent," Mr Wood added.

The landmark ruling by the European Court of Human Rights ruled that the private use of company telecoms equipment and internet access could be protected under European human rights legislation if the company fails to inform the employee that their communications may be monitored.

A Welsh public-sector employee won damages in the court after her communications were intercepted by her employer, who failed to tell her that private calls and e-mails could be monitored.

Mr Wood's advice is for employers to develop a formal policy detailing acceptable internet usage together with details of any procedures to monitor internet and e-mail, which can be shared with employees alongside other contractual obligations.

With a formal policy in place it also becomes easier for employers to update details on acceptable usage in the event of changes being needed.