More companies are reporting an increase in long-term absence, with two fifths seeing a rise, and a fifth seeing a fall, the largest increase in five years, a report has found.
Overall sickness absence remains low at 2.2%, 5.11 days, and 51% of employees having zero absence for the year.
The findings come from the Sickness Absence Survey 2015, conducted by EEF, the manufacturer's association and Jelf Employee Benefits, across 345 companies with 83,654 employees.
The report found that 33% of employers rely exclusively on the NHS to manage long-term employee sickness absence and 30% have no support systems in place for employees with mental-health related long term sickness absence.
Companies with an absence target rose to 65% of those surveyed compared to 2014, and 55% achieved their target.
Back pain and musculoskeletal disorders remain the main cause of long-term absence accounting for 38% of cases.
Stress and mental health has increased since 2009 to being the main cause of absence in 25% of companies.
One in ten companies provides training for line managers in mental-health issues and 2% have an open mental-health disclosure policy.
The report highlighted the importance of the Fit for Work service in reducing long-term absence, although EEFwarned that it doubts the current tax-incentive is sufficient to encourage employers to pay for treatment.
Iain Laws, managing director - UK healthcare and group risk at Jelf Employee Benefits, said: "The importance of Occupational Health and growth in health benefit provision resonates with employers who are increasingly recognising the productivity impact of ill health.
He added: "Reliable, easy-to-use absence-recording systems empower employers and managers to provide the support to employees to minimise absence and manage longer-term or complex cases.
"This in turn can have a positive impact on benefit costs as early detection and action often means lower treatment costs as well."
Professor Sayeed Khan, chief medical adviser at EEF, the manufacturers' organisation, said: "While overall absence levels remain low, there continues to be a marked difference between short- and long-term absence which is creeping up.
"Without a renewed effort to tackle its root causes it will continue to act as a drag on the economy and efforts to improve productivity and boost growth."