While mental illnesses such as stress, depression and anxiety were not viewed more or less kindly by managers, employees were significantly more likely to lie about non-physical health.
A survey of 1,000 non-executive employees found that 7 per cent would tell their boss a lie if they had to miss work for a physical ailment such as back pain, flu or accidental injury.
However, they were almost six times more likely to lie if they called in sick due to stress, anxiety or depression, with 40 per cent saying they would not tell their manager the truth.
The survey also found that 22 per cent of employees would not give the honest reason if they phoned in sick due to a cold, while 12 per cent would lie about having a migraine.
"Employers need to challenge this blinkered attitude, both for their own benefit as well as that of their employees," said Glen Parkinson of AXA PPP Healthcare.
"In many cases it is more productive for an employee to take a day off to recover from a spell of illness rather than to come into work, with diminished productivity and, for likes of colds and flu, the potential to spread their illness to workmates."
When asked to explain why they would withhold the truth from their managers, 23 per cent of employees said they preferred to keep their health issues private.
A further 23 per cent admitted they were afraid of being judged, 15 per cent said they were concerned about not being believed, 7 per cent said they were afraid of their manager's reaction and 3 per cent confessed they would feel ashamed to reveal the true reason.
Mr Parkinson added: "Showing sympathy and flexibility when employees are unwell is crucial to maintaining a healthy and committed workforce, which in the long term creates a healthier business."
