Devolving HR duties to line managers can lead to institutional racism in organisations, one of the authors of a study told the conference.
The discrimination arises from lack of training for managers in performance management and handling disciplinary procedures, said Jo Rick, IES principal research fellow.
In the study, undertaken at a large public-sector organisation, ethnic minority staff were found to be far more likely to face disciplinary hearings and be viewed as poor performers by managers.
White managers were most prone to negative assessments of black and Asian staff. Ethnic minorities make up more than half of the organisation's staff.
The study comes in the wake of the MacPherson report, which stated institutional racism "can be seen or detected in processes, attitudes and behaviour which amount to discrimination through prejudice, ignorance, thoughtlessness and racist stereotyping".
Managers at the organisation said they had little confidence in handling personnel procedures because of a lack of training.
This led to unwitting discrimination, the study found.
"In the absence of an agreed set of criteria for assessment…, individual managers' judgements about what constitutes a good performer are more likely to hold sway," the authors concluded.
Managers were more likely to invoke disciplinary proceedings because they wanted to keep all dealings "on the record" and avoid accusations of harassment, the research concluded.
Managers only felt comfortable handling sickness absence cases, because they had been trained in the relevant procedures.
"The problem is where it [devolving HR duties] is done without appropriate training. With that in place, as it was in this case with sickness absence, it is not so much of a problem," said Rick.