A survey by Shine Feedback of more than 13,000 private and public-sector employees, found line managers' capability in handling difficult conversations with staff to be ‘low'.
And a third of staff surveyed by the firm said they do not have regular performance reviews.
Andy Clare, managing partner of Shine Feedback, said: "There are many reasons why managers are unable to handle poor performance or give feedback. It's sensitive, can get emotional, they might have other priorities, or perhaps they don't have enough evidence. Also, when jobs are at risk during a recession, managers can be inclined to overlook poor performance, giving underachievement the benefit of the doubt. After all, who wants to be responsible for someone losing their job when there aren't too many around?
"But our research and observations tell us managers simply lack the practical skills and understanding of how to give challenging feedback.
"At the most basic level, it's important to remember that instead of moaning or complaining, it's better to state that poor performance is unacceptable and provide constructive feedback to help people learn."