Workplace absenteeism cost the economy more than £12 billion last year - with £1.7 billion of that due to workers "pulling sickies" rather than being genuinely ill, a new report claimed.
The CBI said the problem cost firms £495 per worker, an increase of £20 on the previous year.
The cost to the economy has risen from £11.6 billion to £12.2 billion between 2003 and 2004, with firms having to pay for temporary cover and suffering lost productivity.
The survey of more than 500 firms by the CBI and insurance firm AXA showed that 6.8 working days were lost per employee last year although the total number of lost days fell from 176 million to 168 million.
The CBI said its research showed that 23 million working days were as a result of unwarranted absence. The claim followed an earlier CBI report on Monday which claimed that a rise in public sector absenteeism was undermining services.
Most of the private-sector organisations questioned said they suspected some workers called in sick on a Friday or Monday to take a long weekend and two out of three said they noticed an increase in absence levels around bank holidays. Minor illnesses, such as flu, were a main cause of absence last year, although other problems included stress and back pain.
John Cridland, deputy director-general of the CBI, said: "Employers understand that staff are not invincible. They accept that the majority of absence is due to genuine minor illness and nobody is saying that genuinely ill staff should drag themselves to work.
"But there are some employees who will gladly award themselves a day off when they are in good health at the expense of their employers and hard-working colleagues."
Manufacturing firms reported higher-absence levels than service-sector companies, losing an average of seven days per worker.
Manual workers took an average of 8.4 days off compared with six for nonmanual staff.
The South-west lost the most working days to absence (eight days per employee), followed by the North-west (7.9), the West Midlands and northern England ( both 7.5 days), Yorkshire and the Humber (7.4) and the Southeast (7.3).
The lowest absence levels were in Northern Ireland (5.9) and Greater London (5.6). TUC general secretary Brendan Barber said: "The CBI seem to think workers are all throwing sickies, but the truth is that sickness absence is in decline and we go sick less than workers in nearly every other European country.
"Throwing a sickie is wrong, but the problem needs to be put into perspective. Threequarters of employees say they go to work when they are too ill."