Workers are taking more time off sick at a cost to the economy of

£13 billion a year.

Employees took an average of ten days off in the past year, up by almost a day from the previous year.

Sickness absence is costing firms £522 per worker per year, according to a survey of 1,300 employers by the Chartered Institute of Personnel and Development (CIPD).

Stress was the most common cause of long-term absence for non-manual staff, while for manual workers it was back pain.

Long term absence of more than four weeks accounted for a fifth of time off sick.

CIPD policy adviser Diane Sinclair said: "Our survey suggests organisations need to do more to tackle stress among their staff.

"Both the reasons for work-related stress and its symptoms need to be managed."

The survey, covering organisations employing a total of 1.7 million workers, showed the most common cause of absence were minor illnesses such as colds or 'flu.

Hardest-hit were food, drink and tobacco firms, paper and printing and public sector organisations.

The South-East had lower than average absence levels.