In a survey of union safety reps, the TUC found that the incidence of RSI had increased to 40%, up 3% on a similar survey carried out in 2002.
Fifty-eight percent of reps reported that their colleagues were affected by stress, an increase of 2%; and 35% of reps had seen colleagues suffering from back strain, up 4% on 2002.
Other safety concerns raised by the union reps include display screen equipment (32% cited problems), working alone (27%), long hours (25%), violence (22%) and chemicals and solvents (21%).
The survey also said that stress is worst for workers in banking and finance (83% in the sector reported that stress was a big problem), whilst the most highly stressed parts of the UK are Scotland and the South West.
All employers are legally required to carry out regular risk assessments to try to limit workplace illness and accidents, and, according to the TUC report, whilst 53% of UK employers are carrying out adequate risk assessments, almost one in 10 reps (8%) said that their employer had never carried out a risk assessment.
The survey found that the private sector is better (57%) at carrying out risk assessments than the public sector (51%), with employers in the energy and banking sectors having the best records. Local government (42%) and education (43%) are the worst, with London seeing the fewest risk assessments in the UK.
But employers should be aware of their potential liability for failing to deal with health and safety issues in the workplace.
For example, RSI, the symptoms of which include pain and immobility in the joints, nerves and muscles from the fingers to the neck, is in many cases caused by repetitive movements and fatigue resulting from natural stresses and strains on the body that can often be prevented by adapting the employee's computer set-up.
A few years ago, a court ordered Barclays Bank to pay compensation of £244,000 to a former employee who was forced to give up work as a result of pain in her right hand. Fiona Conaty had worked as a bank clerk and argued that a defective workstation caused her to carry out keyboard work with an unsuitable posture.
Her symptoms developed over two years, after which time Miss Conaty was unable to tie her shoes or even comb her hair. She was only 28 years old at the time of the case.
"The top five workplace hazards are all easily preventable, yet too few employers seem to be getting to grips with preventing accidents and ill health at work," said TUC General Secretary Brendan Barber. "Meanwhile stress, RSI, back strain, slips and trips and problems caused by display screen equipment continue to cause pain and distress to thousands of workers and cost the UK economy millions."
Speaking to Reuters, Dr Janet Asherson, head of health and safety at the Confederation of British Industry (CBI) criticised the figures cited by the survey.
"They are based on self-diagnosis," she said. "We need to have medically validated diagnoses to make sure we are all talking about the same thing."