The Irish Small & Medium Enterprises Association says the issuing of "sick certs" must become the subject of an investigation.
The organisation maintains that certs are commonly issued to "under-serving" employees at great cost to businesses and the State.
Chief executive of ISME Mark Fielding said legal issues put doctors in a difficult position.
"It is quite obvious, based on anecdotal evidence and investigation results, that unauthorised absences are being openly condoned by the medical profession, too busy to investigate and advise and too fearful of our litigious environment.
"Due to this, it has now become completely unrealistic for a business to expect a full complement of staff on any given day.
"Many GPs are afraid they'll be sued if they don't give a cert," he said. "If somebody comes in and says they're ill, it's probably beyond GPs' ability to say they're not going to give a cert."