Employment relations body Acas has published an employers guide to social media that it says is an "industry first".
The 50-page report, which was researched by the Institute of Employment Studies on behalf of Acas, features sections on employment law and social media, policy formulation and cyber bullying.
According to the report, some 55 per cent of employees access social media sites while at work.
However, this use is limited to younger and less skilled employees, since fewer than 15 per cent of "higher skilled" workers use the sites.
Despite widespread use of social media sites, most employees (70 per cent) are unaware of company policy regarding the activity, according to the findings of the My Job Group Survey 2010, which asked 1,000 people at a variety of companies about their employer's attitude to social media.