Misconduct, harassment and unethical activity remain rife in may organisations because a significant proportion of employees feel unable to report or challenge unacceptable behaviour.
Research by Mercer Human Resource Consulting suggests that fewer than six out of ten (58 per cent) of employees in Britain would feel able to report instances of bullying or harassment in the workplace.
Furthermore, only two-thirds feel free to report dishonest or unethical behaviour, according to the survey of more than 1,100 British workers of different grade levels.
The research also found that reluctance to report misconduct is not confined to employees lower down the organisational hierarchy.
In fact, fewer than two-thirds (62 per cent) of middle-ranking managers feel comfortable about reporting harassment by more senior managers.
Mercer's Paul Sanchez said: "It is worrying that such a high proportion of employees feel they cannot speak up about bullying and other unethical behaviour at work.
When extrapolated to the whole of the UK workforce, we could be looking at several million individuals who are too intimidated to report management misconduct."
Employers run an increasing risk of litigation if they fail to address harassment at work, he added, particularly if the behaviour is directed at people because of gender, race or religion.
"There have also been some high-profile court cases on bullying in recent years, and these look set to continue if those acting inappropriately at work are not dealt with accordingly," Sanchez said.
"Organisations need to establish clear guidelines regarding bullying and harassment, stating in unequivocal terms that such behaviour is unacceptable."
The survey also found that only six out of ten employees feel they are treated with dignity and respect, regardless of their position or background, while fewer than seven out of 10 (68 per cent) believe they are treated fairly.
Surprisingly, however, three-quarters (75 per cent) of employees say their organisation supports diversity.
"While many companies have a diversity policy which is well communicated to employees, this does not guarantee that managers and supervisors will comply with, or actively support, it," said Mr Sanchez.
The report suggested that the root causes of these problems include an inconsistency between what companies say and what they do and a lack of consultation between senior management and their workforces.
Only four out of 10 of those surveyed felt that their organisation makes sufficient effort to get the views and opinions of workers, while fewer than six out of 10 (56 per cent) feel safe to speak up and express their views.
"Organisations can assess the workforce 'climate' by conducting regular, confidential employee surveys", said David Tong, European Principal at Mercer.
"Many employees feel it is too risky to question how things are done at work. But a culture of total compliance can stifle innovation, and ultimately this will have a negative impact on customer service and business performance.
"Employees should be encouraged to suggest new ways of working, since they are often closest to customers and can provide valuable feedback."