Four employers in 10 (43%) have experienced at least one issue as a result of a close personal relationship between employees, according to latest XpertHR research.
However, according to the research findings, only 24% of employers have in place a written policy on workplace relationships, despite the issues that can arise.
The most common problem arising from relationships is complaints about favouritism, which had been experienced by 37% of respondents during the past five years.
In addition, three respondents in 10 (28%) said that they havd witnessed decreased morale, and the same number (27%) had to deal with bullying behaviour after a relationship between employees ended. One respondent in 10 (12%) said that it had witnessed a sexual harassment claim as a result of affairs at work.
None of the 200 employers that responded to the survey exercise an outright ban on relationships between colleagues, although the survey did find that 26% discourage or disallow affairs in the workplace "in any circumstance" and a further 26% prohibit them "in some circumstances".
Perhaps unsurprisingly, six organisations in 10 said that overt sexual behaviour in the workplace would trigger some sort of response.
Charlotte Wolff, XpertHR editor and author of the report ,commented: "Although problems relating to workplace relationships are not an everyday occurrence, they can happen - often having a negative impact on the working environment, efficient team working and employee performance.
"A large number of HR professionals responding to our survey told us that they would like to see a clearer, more open approach to workplace relationships at their organisation. This would ensure that the parameters are clear, and individuals involved in a relationship are treated fairly and consistently should action need to be taken."
Among those employers that do have a policy on relationships, 36% disallow relationships between managers and their subordinates, 17% between employees and clients, 14% between employees in the same department or team, and 11% prohibit relationships involving senior employees or members of the executive team.
Where action is taken, this will usually involve a formal reprimand (33%), a transfer to another part of the organisation to ensure that the couple do not work closely together (30%) or dismissal (21%).
Visit XpertHR to view the full data from the workplace relationships survey.