Sickness absence remains low but there is growing concern about rising levels of mental health and stress-related problems, according to a study.
A survey of almost 350 companies employing 90,000 workers found that employers were struggling to tackle mental health issues, leading to increases in long-term absence.
The EEF manufacturers' organisation said its research revealed that only one in 10 companies provided training on mental health to managers.
Two-fifths said long-term absence rates were increasing, even though total absence rates were low at just 2.2pc, or five days a year per employee on average, although half of workers never take time off sick.
Back pain and musculoskeletal disorders remain the main cause of long-term absence, with stress and mental health disorders the main cause of absence for one in four companies, up since 2009.
Stress and mental illness is regarded as the most difficult form of absence to make workplace adjustments for, with almost a third of companies saying this is the case.
A third of employers said they do not have approaches for managing mental health-related long-term absence, with evidence suggesting that GPs also find it difficult to suggest workplace adjustments.
Professor Sayeed Khan, chief medical adviser at the EEF, said: "As a society we can no longer ignore the very real impact of these issues."