Employers could be breaking the law because of miscommunication between the IT and human resources (HR) departments.
In a survey of IT and HR managers commissioned by SurfControl only 15 per cent of IT managers said they bothered to consult with HR before installing internet and email monitoring software.
And more than nine out of 10 HR managers thought IT had the final say on whether such systems were put in place, while fewer than half were aware of any legal responsibility to protect staff from internet and email-based harassment.
Only one in 10 respondents felt that the burden was on both employer and employee to use online resources responsibly.
Lisa Harris, solicitor at Morgan Cole, said: "The ideal is for HR and IT talk to each other. There is a responsibility on employers, both under discrimination legislation and generally, to provide a safe working environment in an atmosphere free of harassment.
"HR need to know what's going on as they are going to be the ones to invoke any discipline procedure."
In some cases companies may be breaking the law if they are not taking steps to stop email harassment or employees accessing illegal websites from work, said Harris.
Martino Corbelli, marketing director of SurfControl, said: "Any IT department shouldn't be expected to cover all the bases. IT shouldn't have to be seen as the internet police and shouldn't be writing policy themselves; that should be spearheaded by HR. Avoiding miscommunication is vital."
In a separate survey released by compliance and security software company PolicyMatter, 84 per cent of IT managers said that office systems were misused constantly, often or sometimes. Over half of abusers either did not think they caused any harm or did not care.
Nearly half of IT managers surveyed said users "don't understand what they are doing wrong", and 43 per cent said users thought their computer misuse would have no negative effects on the company.
Nine per cent of IT managers thought that users felt they could get away with it. Only one per cent said users deliberately flouted company policy regardless of risk.
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