According to HSA's Healthy Working Report, 22% of staff have a colleague who works through illness and 15% feel they would come to work even if they had flu symptoms or diarrhoea.
The research also shows 13% of staff think their company's healthcare provision is uncompetitive, suggesting it would not influence their decision to stay in their job.
The survey showed a link between health provision and business success, with 70% of organisations with competitive healthcare benefits reporting growth over the past year compared with 40% of those whose benefits are uncompetitive.
Commenting on the findings, Cary Cooper, professor of organisational psychology at Lancaster University Management School, said: "It is worrying that a substantial number of organisations throughout the UK are putting employees under pressure to come to work while they are still unwell. This is counterproductive because a sick employee isn't a productive employee and invariably he or she will make wrong decisions that someone else will have to rectify later on."
David Thomas, personnel manager at Runnymede Borough Council in Surrey, said: "It's important that our employees are able to access healthcare when they need it and do not continue to suffer while at work and risk prolonging whatever problem they may have."
Downturn impacts employee wellbeing
Three quarters of HR professionals say they are aware of "extreme working" within their organisation, with employees working through incapacity or illness.