A total of 5.2m working days were lost by North West-based businesses through injury and ill health last year, according to an opinion survey.
It equates to an average annual loss of an estimated two days per worker.
The Health and Safety Executive (HSE), which released the figures, said it can make a serious dent in profits, particularly for small businesses.
The most common causes of workplace ill health and injury include slips and trips, stress and back pain.
The results highlight the areas where businesses plan to make improvements.
Better financial systems and more effective marketing were seen as the most important areas of development, followed by staff training and enhancing IT systems.
With so many things to focus on, health and safety gets pushed to the bottom of the list of priorities, says the HSE.
"It's easy to overlook or neglect health and safety measures," said David Ashton, HSE's Regional Director in the North West.
"But in fact preventive measures can benefit businesses financially by averting work-based incidents and the associated staff and workplace costs that follow."
HSE's Better Business campaign is a national initiative that focuses on raising awareness about the financial and personal costs, and causes of workplace incidents.